Research Article Nanostructured Polylactic Acid/Candeia …downloads.hindawi.com/journals/jnm/2015/439253.pdf · 2019-07-31 · Research Article Nanostructured Polylactic Acid/Candeia

Research ArticleNanostructured Polylactic AcidCandeia Essential Oil MatsObtained by Electrospinning

Claacuteudia L S de Oliveira Mori1 Nathaacutelia Almeida dos Passos2 Juliano Elvis Oliveira3

Thiza Falqueto Altoeacute1 Faacutebio Akira Mori1 Luiz Henrique Capparelli Mattoso4

Joseacute Roberto Scolforo1 and Gustavo Henrique Denzin Tonoli1

1DCF Universidade Federal de Lavras PO Box 3037 37200-000 Lavras MG Brazil2DCA Universidade Federal de Lavras PO Box 3037 37200-000 Lavras MG Brazil3DEG Universidade Federal de Lavras PO Box 3037 37200-000 Lavras MG Brazil4Laboratorio Nacional de Nanotecnologia para o Agronegocio (LNNA) Embrapa Instrumentacao (CNPDIA) PO Box 74113560-970 Sao Carlos SP Brazil

Correspondence should be addressed to Gustavo Henrique Denzin Tonoli gustavotonolidcfuflabr

Received 9 September 2014 Revised 12 December 2014 Accepted 23 December 2014

Academic Editor Nay Ming Huang

Copyright copy 2015 Claudia L S de Oliveira Mori et al This is an open access article distributed under the Creative CommonsAttribution License which permits unrestricted use distribution and reproduction in any medium provided the original work isproperly cited

This work aims to evaluate the effect of inclusion of different contents of candeia (Eremanthus erythropappus) essential oil (whosealpha-bisabolol is themain terpene) on the properties of polylactic acid (PLA) nanostructuredmats and their relationshipwith fibermorphology and structureThe interaction occurring between the PLA and the candeia essential oil was confirmed by thermal andmicroscopy analysis Addition of candeia essential oil increased nanofiber diameter and decreased the glass transition and meltingtemperatures of the nanofibers suggesting lower energy input for processing Scanning electronmicroscopy (SEM) images providedevidence of a homogeneous structure for the nanostructured mats X-ray diffraction did not show differences in the crystallizationof the nanofibers This ongoing research confirms the possibility of incorporation of candeia essential oil in the production ofnanofibers that will be studied for multipurpose applications

1 Introduction

Candeia (Eremanthus erythropappus) is a forest specieswhosewood is popularly used as fence post due to its high naturaldurability and currently is the rawmaterial for production ofthe essential oil whose main terpene is the alpha-bisabololwhich confers antibacterial properties that are required in themanufacture of pharmaceuticals fragrances and cosmetics[1ndash4] The higher incidence of this species in the stateof Minas Gerais Brazil is predominantly in mountainouslocations rocky and poor soil conditions which are notobstacles to its development It is very common to find largecandeia forests in places where it would be difficult to developother arboreal species or agricultural crops [5] Because ofits economic importance the species has been extensivelyexplored in Minas Gerais which has been causing a strongreduction of its natural occurrence

Nanostructured materials obtained from renewableresources have been used for healthcare productionand processing of food [6] agriculture [7] environmentalprotection [8] and forestry [9]The application of nanomate-rials across various sectors led to both environmental andeconomic benefits including enhanced product quality andmore sustainable technologies [8]

A fibrillar or nanofibrillar pattern leads to the possibilityof tailoring a wide variety of network-like structures withsmall pore size (compared to commercial nonwoven fabricsin macroscale) The small fiber diameter and large aspectratio lead to exceptionally high surface to volume (mass)ratio which makes the electrospun nanofibers desirablefor several applications Nanofibers obtained from biopoly-mers are of particular interest for potential applications inmedicine drug delivery and agriculture [10 11] Biomedicalapplications of such nonwoven nanofibers comprise wound

Hindawi Publishing CorporationJournal of NanomaterialsVolume 2015 Article ID 439253 9 pageshttpdxdoiorg1011552015439253

2 Journal of Nanomaterials

dressing and release of drugs like antibiotics and anti-inflammatory [12] Applications of nanofibers in agriculturecould include water treatment [13] the estrous control oflivestock animals [14] and crop protection [15] The actualstage of several technologies requires the development ofentirely new approaches for the construction of two- andthree-dimensional nanoarchitectures [15] In many casesthese nanostructures can be obtained by electrospinning [16]

The electrospinning is a simple method that uses elec-trical forces for obtaining polymer fibers with nanometerscale diameters leading to high specific surface area andhighly porous structures for myriad applications [17] Thismethod permits obtaining nanofibers straightforwardly con-tinuously and cost-effectively [18] Electrospinning is basedon the application of a high voltage across a conductive needleattached to a syringe containing the polymer solution and aconductive collector The majority of scientific papers relatedto electrospinning of biodegradable polymers have beenfocused on synthetic materials mostly on polylactic acidpolyglycolic acid and polycaprolactone and their copolymers[19] In comparisonwith synthetic counterparts biopolymersgenerally present improved biocompatibility and are eco-friendly [20ndash22]

The PLA is an aliphatic polyester of high molecularweight which can be achieved by direct polycondensationof lactic acid as the opening polymerization of the cyclicdimer of lactic acidThesemethods allow obtaining polymersof high molar mass The lactic acid monomers used toproduce PLA are obtained from the fermentation of wheatcorn sugarcane or potato [23] The poly(L-lactic acid) andpoly(L-lactide) have the same structural formula and thesetwo distinct names refer exclusively to a monomer used inthe synthesis and may be abbreviated by the acronym PLA[24] PLA has high mechanical performances when com-pared to polyethylene polypropylene and polystyrene andis hydrolysable in the presence of water yielding oligomersand monomers with low molecular weight Besides PLAcan be produced at costs comparable to those of polymersderived from petroleum [25ndash27] According to Oliveira et al[28] blends with other polymers such as polycaprolactone orpolyetherurethane have been used to improve the flexibilityof the PLA with low molecular weight plasticizers such ascitrate esters polyethylene glycol polypropylene glycol andlactic acid oligomer However the use of candeia essentialoil as a functional addition in the processing of PLA nanos-tructured mats was not reported in the literature Then theobjective of this study was to investigate the effect of addingcandeia (Eremanthus erythropappus) essential oil at differentconcentrations (5 10 and 15 by mass) on the properties ofnanostructured PLA mats obtained by electrospinning

2 Materials and Methods

21 Materials Polylactic acid (PLA) was obtained fromNature Works 4046D The HFIP (111333-hexafluoro-2-propanol) was purchased from Chemical Synth (Sao PauloBrazil) and used as a solvent

The candeia (Eremanthus erythropappus) wood (with 9years) used for extraction of the essential oil was crop from

Table 1 Blend design for production of the nanostructured mats

Sample Blend ratio (PLA candeiaessential oil)

Mass fractionof PLA (wt)

PLA (neat) 100 000 100PLAO1 095 005 95PLAO2 090 010 90PLAO3 085 015 85

Mixture ofsolution Single

spinneretCollector

Jet

Workingdistance

High voltage

Syringepump

+

minus

Figure 1 Schematic diagram of the electrospinning setup

an artificial plantation located in Carrancas MG state Brazilunder the coordinates 21∘331015840002110158401015840 S and 44∘421015840434310158401015840Wand between 896 and 1590m high tropical altitude climateKoppen Cwa with moderate temperatures hot and rainysummer with an average annual temperature of 148∘C andmean annual precipitation of 1470mm Candeia essentialoil was obtained by hydrodistillation of candeia wood chipsusing a modified Clevenger apparatus for 4 h Chemicalcomposition of the essential oil was performed by gaschromatography coupled to mass spectrometry (GC-MS)The chromatograph used was the model equipped with massselective detector model 7643 autosampler and MSD 5975CAgilent 7890A

22 Production of the Nanostructured Mats Four formula-tions were tested as presented in Table 1 Definition of theessential oil concentrations was based on previous work [29]The HFIP solvent was added to each assay tube to takethe final concentration of biopolymer to 20 by weightThe formulations were prepared using a polymer (PLA)concentration of 20 (by mass) The formulations wererigorously stirred for several hours (up to 24 h) to ensurethe complete dissolution of the constituents The polymersolutions were spun into nanofibers by electrospinning atroom temperature (sim24∘C) and around 65 relative humidity(RH) and following the procedures described inOliveira et al[30] andMori et al [11] A syringe pump (KDscientificmodel781100) was used to feed the polymer solution (20120583Lmin)through aneedle (Figure 1)High voltagewas applied betweenthe needle and the collector at a constant value (20 kV)

Journal of Nanomaterials 3

The electrospinning parameters were kept constant for allexperiments and the nanofibers were collected on a rotatingdrum with a working distance of 12 cm The nonwovennanofiber mats of each formulation were stored in sealedplastic bags in a desiccator until the characterization tests

23 Scanning Electron Microscopy (SEM) The morphologyof the electrospun nanofibers was analyzed using scanningelectron microscopy (SEM Zeiss model DSM960) Sampleswere prepared by cutting the nonwoven nanofiber mats witha razor blade and mounting them on aluminum stubs usingdouble-side adhesive tape Samples were then gold sputteringcoated (Balzers model SCD 050 Balzers Union AG Balzers)The nanofiber diameters weremeasuredwith the aid of imageanalyses software (Image J National Institutes of Health)Theaverage nanofiber diameter and diameter distribution weredetermined from approximately 100 random measurementsusing representative micrographs

24 Thermal Analysis Differential scanning calorimetry(DSC TA Instruments Calorimetric Analyzer Q100 model)was performed under nitrogen atmosphere at a flow rate of20mLmin andwith a heating rate of 10∘Cmin Samples weresealed in aluminumpans and heated from minus85∘C to 230∘C forall nanofibers samples The glass transition temperature (Tg)was obtained by analysis of the second heating cycle

25 X-Ray Diffraction (XRD) XRD patterns of the electro-spun nanostructured mats were recorded using a Shimadzu(XRD-6000) X-ray diffractometer Scans were carried outfrom 3∘ to 35∘ (2120579) at a scan rate of 5min using Ni filteredCu-K120572 radiation (wavelength of 0154 nm) at 50 kV and20mAn The full-width at half-maximum height (FWHM)of the diffraction peaks was calculated by fitting the X-ray diffraction patterns with a Gaussian-Lorentzian function(Origin 75 software Origin Lab USA) The 119889-spacing for agiven scattering angle 2120579 was calculated by application ofBragg equation

119889 =

120582

2 sin 120579 (1)

where 120582 is the wavelength of the Cu-K120572 radiationThe crystallite size 119863 was estimated by calculating the

broadening of the diffraction peaks according to Scherrerequation

119863 =

119896120582

120573 cos 120579 (2)

where 119896 is the Scherrer constant that is dependent upon thelattice direction and crystallite morphology and 120573 is the full-width at half-maximum height given in radians A 119896 value of09 was used in this study which is based on values found inthe literature for crystals of biopolymers [31 32]

3 Results and Discussion

31 Characterization of the Candeia Essential Oil Theaverageyield of essential oil was 076 in relation to the dry mass

Table 2 Average diameter and standard deviation of the electro-spun nanofibers and bead content in the nanofiber mats

Electrospun nanofibers Diameter(nm)

Bead content(bead120583m2)

PLA (neat) 107 plusmn 42 006PLAO1 123 plusmn 47 002PLAO2 147 plusmn 51 001PLAO3 152 plusmn 53 001PLAO1 5 of candeia essential oil and 95 of PLA PLAO2 10 of candeiaessential oil and 90 of PLA PLAO3 15 of candeia essential oil and 85of PLA

1

2

34

560

1

2

3

4

5

times107

0 10 20 30 40 50

Time (min)

(eV

)

Figure 2 Chromatogram of essential oil of candeia wood 1 = alpha-bisabolol 2 = alpha-bisabolol oxide 3 = eremanthin 4 = spathulenol5 = 120573-selinene and 6 = 120575-selinene

of wood which leads to around 130Kg per hectare of can-deia trees According to chromatography results the majorcomponents found in the candeia essential oil were alpha-bisabolol (898) alpha-bisabolol oxide (39) eremanthin(16) spathulenol (09) 120573-selinene (02) and 120575-selinene(02) (Figure 2) These six chemical components representaround 97 of the candeia essential oil

32 Scanning Electron Microscopy (SEM) SEM images (Fig-ure 3) confirmed the interaction between the candeia essen-tial oil and PLA because no delamination or phase separationwas observed in the structure of an individual nanofiberThisinteraction occurred between the candeia essential oil andPLA through the hydroxyls in the lactic acid and terpenes andsesquiterpene alcohols (components of the candeia essentialoil) The nanofibers are relatively uniform in thicknessrandomized and distributed forming a nonwoven web withhomogeneous morphology of this nanostructured mats andabsence of agglomerates

Table 2 presents the average diameters and the beads con-tent formed during electrospinning while Figure 4 depictsthe diameter distribution of the electrospun nanofibers ofthe different formulations The addition of candeia essentialoil seems to decrease the formation of beads The diameter


Table 3 Thermal properties of the different formulations of the nanostructured mats of PLAcandeia essential oil

Electrospun fibers 119879

119892

(∘C) 119879

1198981

(∘C) Δ119867

1198981

(Jg) 119879

119888

(∘C) Δ119867

119888

(Jg) 119879

1198982

(∘C) Δ119867

1198982

(Jg)PLA (neat) 60 150 22 119 8 153 04PLAO1 49 147 30 80122 106 147 8PLAO2 46 146 28 85124 182 146 3PLAO3 42 145 30 78121 133 145 5119879119892= glass transition temperature 119879

1198981=melting temperature at the first cycle Δ119867

1198981=melting enthalpy at the first cycle119879

119888(∘C) = crystallization temperature

at the first and second cycles (separated by ) Δ119867119888= crystallization enthalpy at the first and second cycles (separated by ) 119879

1198982= melting temperature at the

second cycle Δ1198671198982

(Jg) = melting enthalpy at the second cycle PLAO1 = 5 of candeia essential oil and 95 of PLA PLAO2 = 10 of candeia essential oiland 90 of PLA PLAO3 = 15 of candeia essential oil and 85 of PLA

1120583m

(a)

1120583m

(b)

1120583m

(c)

1120583m

(d)

Figure 3 Scanning electron microscopy (SEM) images of the nanostructured mats (a) PLA (neat PLA) (b) PLAO1 (5 of candeia essentialoil and 95 of PLA) (c) PLAO2 (10 of candeia essential oil and 90 of PLA) and (d) PLAO3 (15 of candeia essential oil and 85 of PLA)

of the electrospun nanofibers ranges from 10 to 360 nm(Figure 4) and the length exceeds 10120583m The dimensionsof these micronanofibrils are similar to that obtained viaelectrospinning by del Valle et al [33] About 53 of thenanofibers obtained with pure PLA are lower than 100 nmin diameter while nanomats obtained with addition of5 (PLAO1) 10 (PLAO2) and 15 (PLAO3) of candeiaessential oil presented around 42 30 and 25 of thenanofibers with diameters lower than 100 nm respectivelyThe increase in the concentration of candeia essential oilled to increase of the diameter of the nanofibers This maybe because of the electric conductivity of the solution thatdecreased with the addition of essential oil and resulted inincrease of the nanofibers diameter Low conductivity of thesolution results in insufficient elongation of the jet by theelectric forces and leads to production of large nanofiberdiameters [34 35] Diameter of the nanofibers may alsobe affected by the solution viscosity that can be explainedin terms of the interaction forces taking place between

the essential oil and PLA Depending on the type and inten-sity of these interactions rheology of the polymer solutionsmay change [14] Normally higher viscosities lead to largefiber diameters [36 37]Thedifferent structural arrangementsof the polymer chains in the nanofibers ultimately may alsoaffect the releasing of the essential oil [38] In the present casethe increase of the essential oil led to a small decrease of theviscosity which probably did not affect the diameter of thenanofibers

33 Thermal Analysis The addition of candeia essential oildecreased the glass transition temperature of the nanofiberssuggesting a plasticizing effect of the essential oil on thePLA (Figure 5) The melting temperature is related to thecrystallinity of the studied nanofibers It was observed thatthe increase of the essential oil concentration decreased themelting temperature of the nanofibers (Figure 5 Table 3)suggesting lower energy input for processingThe increase inthemelting enthalpywith the presence of essential oil can also


0

5

10

15

20

25

0ndash10

10ndash3

0

30

ndash50

50

ndash70

70

ndash90

90

ndash110

110

ndash130

130

ndash150

150

ndash170

170

ndash190

190

ndash210

210

ndash230

230

ndash250

250

ndash270

270

ndash290

290

ndash310

310

ndash330

Con

tent

()

Diameter (nm)

(a)

0

5

10

15

20

25

Con

tent

()

0ndash10

10ndash3

0

30

ndash50

50

ndash70

70

ndash90

90

ndash110

110

ndash130

130

ndash150

150

ndash170

170

ndash190

190

ndash210

210

ndash230

230

ndash250

250

ndash270

270

ndash290

290

ndash310

310

ndash330

Diameter (nm)

(b)

0

5

10

15

20

25

Con

tent

()

0ndash10

10ndash3

0

30

ndash50

50

ndash70

70

ndash90

90

ndash110

110

ndash130

130

ndash150

150

ndash170

170

ndash190

190

ndash210

210

ndash230

230

ndash250

250

ndash270

270

ndash290

290

ndash310

310

ndash330

Diameter (nm)

(c)

0

5

10

15

20

25

Con

tent

()

0ndash10

10ndash3

0

30

ndash50

50

ndash70

70

ndash90

90

ndash110

110

ndash130

130

ndash150

150

ndash170

170

ndash190

190

ndash210

210

ndash230

230

ndash250

250

ndash270

270

ndash290

290

ndash310

310

ndash330

Diameter (nm)

(d)

Figure 4 Diameter distribution histograms of the nanofibers (a) PLA (neat PLA) (b) PLAO1 (5 of candeia essential oil and 95 of PLA)(c) PLAO2 (10 of candeia essential oil and 90 of PLA) and (d) PLAO3 (15 of candeia essential oil and 85 of PLA)

be associated with the plasticizing effects previously men-tioned Thermal degradation of the polymer is result of themolecular degradation with heating At high temperaturesthe long chain polymers begin to suffer molecular hydrolysisleading to changes of the polymer properties [39] In otherPLA systems it was possible to detect a more gradual changein the glass behavior where the existence of two independent(inter- and intraspherulitic) mobile amorphous phases wassuggested [40 41] The glass transition dynamics of bothamorphous and semicrystalline PLA were also investigatedby Mano et al [42] and in that case no significant variationof the stiffness index was observed

Table 3 presents the values of glass transition temperature(Tg) melting temperature (Tm) and crystallization temper-ature (Tc) which decreased with increasing of the contentof candeia essential oil Balogh et al [43] also observed thisbehavior with the inclusion of carvedilol in an amorphousmethacrylate terpolymer matrix The crystallinity of thenanofiber increased with the addition of candeia essentialoil as evidenced by the results of DSC Choi and Park [44]observed the reduction of the glass transition temperaturewith the addition of epoxidized soybean oil in poly-3-hydroxybutyrate-co-valerate (PHBV) nanofibers

Nanostructured mats formulated with candeia essentialoil presented one crystallization process in the first heating

cycle and another one in the second cycle This phenomenonis not observed for the PLA neat mats The values oftemperature and enthalpy of crystallization for the firstand second cycles are separated by slashes () in Table 3We also noted the merge of the PLA in the two heatingcycles The glass transition temperature (Tg) was obtainedby analysis of the second heating cycle Mano et al [42]concluded that crystallinity in PLA has two main effects onthe overall glass transition dynamics (i) shift of the glasstransition temperature to higher values and (ii) broadeningof the distribution of relaxation times The influence of thegeometrical confinement on the glass transition behaviormay be analyzed under the framework of the Adam andGibbs theory [45] using the concept of the cooperativelyrearranging regions (CRR) They are defined as the smallestregions around a relaxing entity that can undergo a transitionto a new configuration state without requiring simultaneousconfiguration changes outside its boundaries

34 X-Ray Diffraction Figure 6 depicts the X-ray diffrac-tograms of the nanostructured mats The interplanar dis-tances were not affected by the presence of candeia essentialoil even in the high concentration (PLAO3) as confirmedby Table 4 Oliveira et al [46] reported the results of theirwork to increase the molecular weight of PLA which leads to


Table 4 Interplanar distances (119889) and crystallite diameters (119863) of the crystalline parts of the electrospun nanofibers


1

(A) 119889

2

(A) 119889

3

(A) 119863

1

(nm) 119863

2

(nm) 119863

3

(nm)PLA (neat) 4 2 3 2 6 5PLAO1 4 2 3 2 6 5PLAO2 4 2 3 2 6 5PLAO3 4 2 3 2 6 5Subscripted peak number 1 (14∘) 2 (17∘) and 3 (25∘) PLAO1 5 of candeia essential oil and 95 of PLA PLAO2 10 of candeia essential oil and 90 ofPLA PLAO3 15 of candeia essential oil and 85 of PLA

Hea

t flow

(ua

)

EXO

30 40 50 60 70 80

Temperature (∘C)

(a)

Hea

t flow

(ua

)

EXO

50 75 100 125 150

Temperature (∘C)

(b)

Hea

t flow

(ua

)

EXO

120 130 140 150 160

PLAO1

PLAO2

PLAO3

PLA

Temperature (∘C)

(c)

Figure 5 DSC curves showing the effect of candeia essential oil addition on (a) glass transition temperature (b) cold crystallization and (c)merging of the electrospun PLA nanofibers PLAO1 5 of candeia essential oil and 95 of PLA PLAO2 10 of candeia essential oil and90 of PLA PLAO3 15 of candeia essential oil and 85 of PLA

increased viscosity of the solutions and the average diameterof the fibers obtained Furthermore according to thoseauthors fibers obtained from lower molecular weight PLAhave lower crystallinity These results show that controllingthe molecular weight and concentration of polymer in solu-tion can control themorphology of the fibers obtained aswellas their degree of crystallinity

4 Conclusion

The nanofibers produced with polylactic acid (PLA) andcandeia (Eremanthus erythropappus) essential oil were suc-cessfully obtained by electrospinning Thermal analysis andmorphological characterization of the electrospun nanofibersshowed that the interaction between PLA and candeia


3000

2500

2000

1500

1000

500

05 10 15 20 25 30 35

Cou

nts

1

2

3

2120579 (∘)

(a)

3000

2500

2000

1500

1000

500

05 10 15 20 25 30 35

Cou

nts

1

2

3

2120579 (∘)

(b)

Cou

nts

1

2

3

5 10 15 20 25 30 35

2120579 (∘)

4000

3000

2000

1000

0

(c)

2000

1500

1000

500

05 10 15 20 25 30 35

Cou

nts

1

2

3

2120579 (∘)

(d)

Figure 6 X-ray diffractograms (XRD) of the nanostructured mats (a) PLA (neat PLA) (b) PLAO1 (5 of candeia essential oil and 95 ofPLA) (c) PLAO2 (10 of candeia essential oil and 90 of PLA) and (d) PLAO3 (15 of candeia essential oil and 85 of PLA)

essential oil occurred The images obtained by scanningelectron microscopy show nanofibers with similar structureand homogeneousmorphology in nanostructured nonwovenmats The addition of essential oil increased the nanofiberdiameter and decreased the glass transition andmelting tem-peratures of the nanofibers showing the plasticizing effectof the essential oil in the PLA matrix X-ray diffraction didnot show differences in the crystallization of the nanofibersThis work confirms the possibility of incorporating thecandeia essential oil for producing electrospun nanofibersThe thermal properties of these nanofibers combined withthe chemical activities of the oil and its compatibility withhydrophobic polymeric matrices open new perspectivesfor the development of new basis of polymeric materialsfor various applications such as antibacterial applicationscosmetics and controlled release of drugs

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

The authors acknowledge the support of Fundacao deAmparo a Pesquisa do Estado de Sao Paulo (FAPESP)Fundacao de Amparo a Pesquisa do Estado de Minas Gerais(FAPEMIG) Coordenacao de Aperfeicoamento de Pessoalde Nıvel Superior (CAPES) Conselho Nacional de Desen-volvimento Cientıfico e Tecnologico (CNPq) EmbrapaInstrumentacao and Brazilian Research Network in Ligno-cellulosic Composites and Nanocomposites (RELIGAR)

References

[1] J F Candido Cultura da candeia (Vanillosmopsis erythropappaSch Bip) UFV 1991

[2] P E R Carvalho Especies florestais brasileiras recomendacoessilviculturais potencialidades e uso da madeira EMBRAPA-CNPFSPI 1994

[3] A P P Galdino J O Brito R F Garcia and J R ScolforoldquoEstudo sobre o rendimento e a qualidade do oleo essencial decandeia (Eremanthus ssp) e a influencia das diferentes origens


da sua madeirardquo Revista Brasileira de Plantas Medicinais vol 8no 4 pp 44ndash46 2006

[4] C L S D O Mori J O Brito J R S Scolforo E J Vidaland L M Mendes ldquoInfluence of altitude age and diameter onyield and alpha-bisabolol content of candeia trees (Eremanthuserythropappus)rdquo Cerne vol 15 no 3 pp 339ndash345 2009

[5] J F M Perez J R S Scolforo A D de Oliveira J M de MelloL F R Borges and J F Camolesi ldquoSistema de manejo para acandeiamdasheremanthus erythropappus (DC) MacLeish a opcaodo sistema de corte seletivordquo CERNE vol 10 no 2 pp 257ndash2732004

[6] C Kriegel A Arrechi K Kit D J McClements and J WeissldquoFabrication functionalization and application of electrospunbiopolymer nanofibersrdquo Critical Reviews in Food Science andNutrition vol 48 no 8 pp 775ndash797 2008

[7] P Bansal K Bubel S Agarwal and A Greiner ldquoWater-stableall-biodegradable microparticles in nanofibers by electrospin-ning of aqueous dispersions for biotechnical plant protectionrdquoBiomacromolecules vol 13 no 2 pp 439ndash444 2012

[8] M Gavrilescu and Y Chisti ldquoBiotechnologymdasha sustainablealternative for chemical industryrdquo Biotechnology Advances vol23 no 7-8 pp 471ndash499 2005

[9] M Spasova N Manolova M Naydenov J Kuzmanova and IRashkov ldquoElectrospun biohybrid materials for plant biocontrolcontaining chitosan and Trichoderma viride sporesrdquo Journal ofBioactive and Compatible Polymers vol 26 no 1 pp 48ndash552011

[10] Y P Neo S Ray A J Easteal M G Nikolaidis and SY Quek ldquoInfluence of solution and processing parameterstowards the fabrication of electrospun zein fibers with sub-micron diameterrdquo Journal of Food Engineering vol 109 no 4pp 645ndash651 2012

[11] C L S O Mori N A dos Passos J E Oliveira et al ldquoElec-trospinning of zeintannin bio-nanofibersrdquo Industrial Crops andProducts vol 52 pp 298ndash304 2014

[12] D W-C Chen F-Y Lee J-Y Liao S-J Liu C-Y Hsiao andJ-K Chen ldquoPreclinical experiments on the release behavior ofbiodegradable nanofibrousmultipharmaceutical membranes inamodel of four-wall intrabony defectrdquoAntimicrobial Agents andChemotherapy vol 57 no 1 pp 9ndash14 2013

[13] C Feng K C Khulbe T Matsuura S Tabe and A F IsmailldquoPreparation and characterization of electro-spun nanofibermembranes and their possible applications in water treatmentrdquoSeparation and Purification Technology vol 102 pp 118ndash1352013

[14] J E Oliveira E S Medeiros L Cardozo et al ldquoDevelopment ofpoly(lactic acid) nanostructured membranes for the controlleddelivery of progesterone to livestock animalsrdquoMaterials Scienceand Engineering C vol 33 no 2 pp 844ndash849 2013

[15] J Sun K Bubel F Chen T Kissel S Agarwal and A GreinerldquoNanofibers by green electrospinning of aqueous suspensions ofbiodegradable block copolyesters for applications in medicinepharmacy and agriculturerdquo Macromolecular Rapid Communi-cations vol 31 no 23 pp 2077ndash2083 2010

[16] C R Lowe ldquoNanobiotechnology the fabrication and appli-cations of chemical and biological nanostructuresrdquo CurrentOpinion in Structural Biology vol 10 no 4 pp 428ndash434 2000

[17] P Ramesh Kumar N Khan S Vivekanandhan N Satya-narayana A K Mohanty and M Misra ldquoNanofibers effectivegeneration by electrospinning and their applicationsrdquo Journal ofNanoscience and Nanotechnology vol 12 no 1 pp 1ndash25 2012

[18] D H Reneker and I Chun ldquoNanometre diameter fibres ofpolymer produced by electrospinningrdquo Nanotechnology vol 7no 3 pp 216ndash223 1996

[19] N Ashammakhi I Wimpenny L Nikkola and Y YangldquoElectrospinning methods and development of biodegradablenanofibres for drug releaserdquo Journal of Biomedical Nanotechnol-ogy vol 5 no 1 pp 1ndash19 2009

[20] R Shukla and M Cheryan ldquoZein the industrial protein fromcornrdquo Industrial Crops and Products vol 13 no 3 pp 171ndash1922001

[21] J W Lawton ldquoZein a history of processing and userdquo CerealChemistry vol 79 no 1 pp 1ndash18 2002

[22] D S Cha andM S Chinnan ldquoBiopolymer-based antimicrobialpackaging a reviewrdquo Critical Reviews in Food Science andNutrition vol 44 no 4 pp 223ndash237 2004

[23] Q Gao P Lan H Shao and X Hu ldquoDirect synthesis with meltpolycondensation and microstructure analysis of poly(L-lacticacid-co-glycolic acid)rdquo Polymer Journal vol 34 no 11 pp 786ndash793 2002

[24] E J Khantzian ldquoReflections on group treatments as correctiveexperiences for addictive vulnerabilityrdquo International Journal ofGroup Psychotherapy vol 51 no 1 pp 11ndash20 2001

[25] I Grizzi H Garreau S Li and M Vert ldquoHydrolytic degrada-tion of devices based on poly(DL-lactic acid) size-dependencerdquoBiomaterials vol 16 no 4 pp 305ndash311 1995

[26] S Sinha Ray P Maiti M Okamoto K Yamada and K UedaldquoNew polylactidelayered silicate nanocomposites 1 Prepara-tion characterization and propertiesrdquoMacromolecules vol 35no 8 pp 3104ndash3110 2002

[27] H Tsuji K Ikarashi and N Fukuda ldquoPoly(L-lactide) XIIFormation growth and morphology of crystalline residuesas extended-chain crystallites through hydrolysis of poly(L-lactide) films in phosphate-buffered solutionrdquo Polymer Degra-dation and Stability vol 84 no 3 pp 515ndash523 2004

[28] J E Oliveira E A Moraes J M Marconcini L H C MattosoG M Glenn and E S Medeiros ldquoProperties of poly(lacticacid) and poly(ethylene oxide) solvent polymer mixtures andnanofibers made by solution blow spinningrdquo Journal of AppliedPolymer Science vol 129 no 6 pp 3672ndash3681 2013

[29] M A Souza J E Oliveira E S Medeiros G M Glenn and LH CMattoso ldquoControlled release of linalool using nanofibrousmembranes of poly(lactic acid) obtained by electrospinningand solution blow spinning a comparative studyrdquo Journal ofNanoscience and Nanotechnolo vol 15 no 8 pp 5628ndash56362015

[30] J E Oliveira V P Scagion V Grassi D S Correa and L H CMattoso ldquoModification of electrospun nylon nanofibers usinglayer-by-layer films for application in flow injection electronictongue detection of paraoxon pesticide in corn croprdquo Sensorsand Actuators B Chemical vol 171-172 pp 249ndash255 2012

[31] P Huang J X Zheng S Leng et al ldquoPoly(ethylene oxide)crystal orientation changes in an inverse hexagonal cylindricalphase morphology constructed by a poly(ethylene oxide)-block- polystyrene diblock copolymerrdquoMacromolecules vol 40no 3 pp 526ndash534 2007

[32] C Marega A Marigo V Di Noto R Zannetti A Martoranaand G Paganetto ldquoStructure and crystallization kinetics ofpoly(L-lactic acid)rdquoMacromolecular Chemistry and Physics vol193 no 7 pp 1599ndash1606 1992

[33] L J del Valle A Dıaz M Royo A Rodrıguez-Galan and JPuiggalı ldquoBiodegradable polyesters reinforced with triclosan


loaded polylactide micronanofibers properties release andbiocompatibilityrdquo Express Polymer Letters vol 6 no 4 pp 266ndash282 2012

[34] N Bhardwaj and S C Kundu ldquoElectrospinning a fascinatingfiber fabrication techniquerdquoBiotechnology Advances vol 28 no3 pp 325ndash347 2010

[35] C Yang X Wu Y Zhao L Xu and S Wei ldquoNanofibrous scaf-fold prepared by electrospinning of poly(vinyl alcohol)gelatinaqueous solutionsrdquo Journal of Applied Polymer Science vol 121no 5 pp 3047ndash3055 2011

[36] N T B Linh Y K Min H-Y Song and B-T Lee ldquoFabri-cation of polyvinyl alcoholgelatin nanofiber composites andevaluation of their material propertiesrdquo Journal of BiomedicalMaterials Research Part B Applied Biomaterials vol 95 no 1pp 184ndash191 2010

[37] D Yang Y Li and J Nie ldquoPreparation of gelatinPVAnanofibers and their potential application in controlled releaseof drugsrdquo Carbohydrate Polymers vol 69 no 3 pp 538ndash5432007

[38] K A Rieger and J D Schiffman ldquoElectrospinning an essentialoil cinnamaldehyde enhances the antimicrobial efficacy of chi-tosanpoly(ethylene oxide) nanofibersrdquoCarbohydrate Polymersvol 113 pp 561ndash568 2014

[39] M Pluta A Galeski M Alexandre M-A Paul and P DuboisldquoPolylactidemontmorillonite nanocomposites and microcom-posites prepared by melt blending structure and some physicalpropertiesrdquo Journal of Applied Polymer Science vol 86 no 6 pp1497ndash1506 2002

[40] M Dionısio M T Viciosa Y Wang and J F Mano ldquoGlasstransition dynamics of poly(L-lactic acid) during isothermalcrystallisation monitored by real-time dielectric relaxationspectroscopy measurementsrdquo Macromolecular Rapid Commu-nications vol 26 no 17 pp 1423ndash1427 2005

[41] Y Wang J L G Ribelles M S Sanchez and J F ManoldquoMorphological contributions to glass transition in poly(l-lactic acid)rdquoMacromolecules vol 38 no 11 pp 4712ndash4718 2005

[42] J F Mano J L Gomez Ribelles N M Alves and M SalmeronSanchez ldquoGlass transition dynamics and structural relaxation ofPLLA studied by DSC influence of crystallinityrdquo Polymer vol46 no 19 pp 8258ndash8265 2005

[43] A Balogh G Dravavolgyi K Farago et al ldquoPlasticized drug-loaded melt electrospun polymer mats characterization ther-mal degradation and release kineticsrdquo Journal of Pharmaceuti-cal Sciences vol 103 no 4 pp 1278ndash1287 2014

[44] J S Choi and W H Park ldquoThermal and mechanical propertiesof poly(3-hydroxybutyrate-co-3-hydroxyvalerate) plasticizedby biodegradable soybean oilsrdquoMacromolecular Symposia vol197 no 1 pp 65ndash76 2003

[45] G Adam and J H Gibbs ldquoOn the temperature dependence ofcooperative relaxation properties in glass-forming liquidsrdquoTheJournal of Chemical Physics vol 43 no 1 pp 139ndash146 1965

[46] J Oliveira G S Brichi and J M Marconcini ldquoEffect of solventon the physical and morphological properties of poly(lacticacid) nanofibers obtained by solution blow spinningrdquo Journalof Engineered Fibers and Fabrics vol 9 no 4 2014

Submit your manuscripts athttpwwwhindawicom

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CorrosionInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Polymer ScienceInternational Journal of



CeramicsJournal of


CompositesJournal of

NanoparticlesJournal of



International Journal of

Biomaterials


NanoscienceJournal of

TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Journal of

NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

CrystallographyJournal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014


CoatingsJournal of

Advances in

Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Smart Materials Research



MetallurgyJournal of


BioMed Research International

MaterialsJournal of


Nano

materials


Journal ofNanomaterials


dressing and release of drugs like antibiotics and anti-inflammatory [12] Applications of nanofibers in agriculturecould include water treatment [13] the estrous control oflivestock animals [14] and crop protection [15] The actualstage of several technologies requires the development ofentirely new approaches for the construction of two- andthree-dimensional nanoarchitectures [15] In many casesthese nanostructures can be obtained by electrospinning [16]

The electrospinning is a simple method that uses elec-trical forces for obtaining polymer fibers with nanometerscale diameters leading to high specific surface area andhighly porous structures for myriad applications [17] Thismethod permits obtaining nanofibers straightforwardly con-tinuously and cost-effectively [18] Electrospinning is basedon the application of a high voltage across a conductive needleattached to a syringe containing the polymer solution and aconductive collector The majority of scientific papers relatedto electrospinning of biodegradable polymers have beenfocused on synthetic materials mostly on polylactic acidpolyglycolic acid and polycaprolactone and their copolymers[19] In comparisonwith synthetic counterparts biopolymersgenerally present improved biocompatibility and are eco-friendly [20ndash22]

The PLA is an aliphatic polyester of high molecularweight which can be achieved by direct polycondensationof lactic acid as the opening polymerization of the cyclicdimer of lactic acidThesemethods allow obtaining polymersof high molar mass The lactic acid monomers used toproduce PLA are obtained from the fermentation of wheatcorn sugarcane or potato [23] The poly(L-lactic acid) andpoly(L-lactide) have the same structural formula and thesetwo distinct names refer exclusively to a monomer used inthe synthesis and may be abbreviated by the acronym PLA[24] PLA has high mechanical performances when com-pared to polyethylene polypropylene and polystyrene andis hydrolysable in the presence of water yielding oligomersand monomers with low molecular weight Besides PLAcan be produced at costs comparable to those of polymersderived from petroleum [25ndash27] According to Oliveira et al[28] blends with other polymers such as polycaprolactone orpolyetherurethane have been used to improve the flexibilityof the PLA with low molecular weight plasticizers such ascitrate esters polyethylene glycol polypropylene glycol andlactic acid oligomer However the use of candeia essentialoil as a functional addition in the processing of PLA nanos-tructured mats was not reported in the literature Then theobjective of this study was to investigate the effect of addingcandeia (Eremanthus erythropappus) essential oil at differentconcentrations (5 10 and 15 by mass) on the properties ofnanostructured PLA mats obtained by electrospinning

2 Materials and Methods

21 Materials Polylactic acid (PLA) was obtained fromNature Works 4046D The HFIP (111333-hexafluoro-2-propanol) was purchased from Chemical Synth (Sao PauloBrazil) and used as a solvent

The candeia (Eremanthus erythropappus) wood (with 9years) used for extraction of the essential oil was crop from

Table 1 Blend design for production of the nanostructured mats

Sample Blend ratio (PLA candeiaessential oil)

Mass fractionof PLA (wt)

PLA (neat) 100 000 100PLAO1 095 005 95PLAO2 090 010 90PLAO3 085 015 85

Mixture ofsolution Single

spinneretCollector

Jet

Workingdistance

High voltage

Syringepump

+

minus

Figure 1 Schematic diagram of the electrospinning setup

an artificial plantation located in Carrancas MG state Brazilunder the coordinates 21∘331015840002110158401015840 S and 44∘421015840434310158401015840Wand between 896 and 1590m high tropical altitude climateKoppen Cwa with moderate temperatures hot and rainysummer with an average annual temperature of 148∘C andmean annual precipitation of 1470mm Candeia essentialoil was obtained by hydrodistillation of candeia wood chipsusing a modified Clevenger apparatus for 4 h Chemicalcomposition of the essential oil was performed by gaschromatography coupled to mass spectrometry (GC-MS)The chromatograph used was the model equipped with massselective detector model 7643 autosampler and MSD 5975CAgilent 7890A

22 Production of the Nanostructured Mats Four formula-tions were tested as presented in Table 1 Definition of theessential oil concentrations was based on previous work [29]The HFIP solvent was added to each assay tube to takethe final concentration of biopolymer to 20 by weightThe formulations were prepared using a polymer (PLA)concentration of 20 (by mass) The formulations wererigorously stirred for several hours (up to 24 h) to ensurethe complete dissolution of the constituents The polymersolutions were spun into nanofibers by electrospinning atroom temperature (sim24∘C) and around 65 relative humidity(RH) and following the procedures described inOliveira et al[30] andMori et al [11] A syringe pump (KDscientificmodel781100) was used to feed the polymer solution (20120583Lmin)through aneedle (Figure 1)High voltagewas applied betweenthe needle and the collector at a constant value (20 kV)






119889 =

120582

2 sin 120579 (1)



119863 =

119896120582

120573 cos 120579 (2)








1

2

34

560

1

2

3

4

5

times107

0 10 20 30 40 50

Time (min)

(eV

)








119892

(∘C) 119879

1198981

(∘C) Δ119867

1198981

(Jg) 119879

119888

(∘C) Δ119867

119888

(Jg) 119879

1198982

(∘C) Δ119867

1198982









1120583m

(a)

1120583m

(b)

1120583m

(c)

1120583m

(d)






0

5

10

15

20

25

0ndash10

10ndash3

0

30

ndash50

50

ndash70

70

ndash90

90

ndash110

110

ndash130

130

ndash150

150

ndash170

170

ndash190

190

ndash210

210

ndash230

230

ndash250

250

ndash270

270

ndash290

290

ndash310

310

ndash330

Con

tent

()

Diameter (nm)

(a)

0

5

10

15

20

25

Con

tent

()

0ndash10

10ndash3

0

30

ndash50

50

ndash70

70

ndash90

90

ndash110

110

ndash130

130

ndash150

150

ndash170

170

ndash190

190

ndash210

210

ndash230

230

ndash250

250

ndash270

270

ndash290

290

ndash310

310

ndash330

Diameter (nm)

(b)

0

5

10

15

20

25

Con

tent

()

0ndash10

10ndash3

0

30

ndash50

50

ndash70

70

ndash90

90

ndash110

110

ndash130

130

ndash150

150

ndash170

170

ndash190

190

ndash210

210

ndash230

230

ndash250

250

ndash270

270

ndash290

290

ndash310

310

ndash330

Diameter (nm)

(c)

0

5

10

15

20

25

Con

tent

()

0ndash10

10ndash3

0

30

ndash50

50

ndash70

70

ndash90

90

ndash110

110

ndash130

130

ndash150

150

ndash170

170

ndash190

190

ndash210

210

ndash230

230

ndash250

250

ndash270

270

ndash290

290

ndash310

310

ndash330

Diameter (nm)

(d)










1

(A) 119889

2

(A) 119889

3

(A) 119863

1

(nm) 119863

2

(nm) 119863

3


Hea

t flow

(ua

)

EXO

30 40 50 60 70 80

Temperature (∘C)

(a)

Hea

t flow

(ua

)

EXO

50 75 100 125 150

Temperature (∘C)

(b)

Hea

t flow

(ua

)

EXO

120 130 140 150 160

PLAO1

PLAO2

PLAO3

PLA

Temperature (∘C)

(c)



4 Conclusion



3000

2500

2000

1500

1000

500

05 10 15 20 25 30 35

Cou

nts

1

2

3

2120579 (∘)

(a)

3000

2500

2000

1500

1000

500

05 10 15 20 25 30 35

Cou

nts

1

2

3

2120579 (∘)

(b)

Cou

nts

1

2

3

5 10 15 20 25 30 35

2120579 (∘)

4000

3000

2000

1000

0

(c)

2000

1500

1000

500

05 10 15 20 25 30 35

Cou

nts

1

2

3

2120579 (∘)

(d)





Acknowledgments


References


























































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials








119889 =

120582

2 sin 120579 (1)



119863 =

119896120582

120573 cos 120579 (2)








1

2

34

560

1

2

3

4

5

times107

0 10 20 30 40 50

Time (min)

(eV

)








119892

(∘C) 119879

1198981

(∘C) Δ119867

1198981

(Jg) 119879

119888

(∘C) Δ119867

119888

(Jg) 119879

1198982

(∘C) Δ119867

1198982









1120583m

(a)

1120583m

(b)

1120583m

(c)

1120583m

(d)






0

5

10

15

20

25

0ndash10

10ndash3

0

30

ndash50

50

ndash70

70

ndash90

90

ndash110

110

ndash130

130

ndash150

150

ndash170

170

ndash190

190

ndash210

210

ndash230

230

ndash250

250

ndash270

270

ndash290

290

ndash310

310

ndash330

Con

tent

()

Diameter (nm)

(a)

0

5

10

15

20

25

Con

tent

()

0ndash10

10ndash3

0

30

ndash50

50

ndash70

70

ndash90

90

ndash110

110

ndash130

130

ndash150

150

ndash170

170

ndash190

190

ndash210

210

ndash230

230

ndash250

250

ndash270

270

ndash290

290

ndash310

310

ndash330

Diameter (nm)

(b)

0

5

10

15

20

25

Con

tent

()

0ndash10

10ndash3

0

30

ndash50

50

ndash70

70

ndash90

90

ndash110

110

ndash130

130

ndash150

150

ndash170

170

ndash190

190

ndash210

210

ndash230

230

ndash250

250

ndash270

270

ndash290

290

ndash310

310

ndash330

Diameter (nm)

(c)

0

5

10

15

20

25

Con

tent

()

0ndash10

10ndash3

0

30

ndash50

50

ndash70

70

ndash90

90

ndash110

110

ndash130

130

ndash150

150

ndash170

170

ndash190

190

ndash210

210

ndash230

230

ndash250

250

ndash270

270

ndash290

290

ndash310

310

ndash330

Diameter (nm)

(d)










1

(A) 119889

2

(A) 119889

3

(A) 119863

1

(nm) 119863

2

(nm) 119863

3


Hea

t flow

(ua

)

EXO

30 40 50 60 70 80

Temperature (∘C)

(a)

Hea

t flow

(ua

)

EXO

50 75 100 125 150

Temperature (∘C)

(b)

Hea

t flow

(ua

)

EXO

120 130 140 150 160

PLAO1

PLAO2

PLAO3

PLA

Temperature (∘C)

(c)



4 Conclusion



3000

2500

2000

1500

1000

500

05 10 15 20 25 30 35

Cou

nts

1

2

3

2120579 (∘)

(a)

3000

2500

2000

1500

1000

500

05 10 15 20 25 30 35

Cou

nts

1

2

3

2120579 (∘)

(b)

Cou

nts

1

2

3

5 10 15 20 25 30 35

2120579 (∘)

4000

3000

2000

1000

0

(c)

2000

1500

1000

500

05 10 15 20 25 30 35

Cou

nts

1

2

3

2120579 (∘)

(d)





Acknowledgments


References


























































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials






119892

(∘C) 119879

1198981

(∘C) Δ119867

1198981

(Jg) 119879

119888

(∘C) Δ119867

119888

(Jg) 119879

1198982

(∘C) Δ119867

1198982









1120583m

(a)

1120583m

(b)

1120583m

(c)

1120583m

(d)






0

5

10

15

20

25

0ndash10

10ndash3

0

30

ndash50

50

ndash70

70

ndash90

90

ndash110

110

ndash130

130

ndash150

150

ndash170

170

ndash190

190

ndash210

210

ndash230

230

ndash250

250

ndash270

270

ndash290

290

ndash310

310

ndash330

Con

tent

()

Diameter (nm)

(a)

0

5

10

15

20

25

Con

tent

()

0ndash10

10ndash3

0

30

ndash50

50

ndash70

70

ndash90

90

ndash110

110

ndash130

130

ndash150

150

ndash170

170

ndash190

190

ndash210

210

ndash230

230

ndash250

250

ndash270

270

ndash290

290

ndash310

310

ndash330

Diameter (nm)

(b)

0

5

10

15

20

25

Con

tent

()

0ndash10

10ndash3

0

30

ndash50

50

ndash70

70

ndash90

90

ndash110

110

ndash130

130

ndash150

150

ndash170

170

ndash190

190

ndash210

210

ndash230

230

ndash250

250

ndash270

270

ndash290

290

ndash310

310

ndash330

Diameter (nm)

(c)

0

5

10

15

20

25

Con

tent

()

0ndash10

10ndash3

0

30

ndash50

50

ndash70

70

ndash90

90

ndash110

110

ndash130

130

ndash150

150

ndash170

170

ndash190

190

ndash210

210

ndash230

230

ndash250

250

ndash270

270

ndash290

290

ndash310

310

ndash330

Diameter (nm)

(d)










1

(A) 119889

2

(A) 119889

3

(A) 119863

1

(nm) 119863

2

(nm) 119863

3


Hea

t flow

(ua

)

EXO

30 40 50 60 70 80

Temperature (∘C)

(a)

Hea

t flow

(ua

)

EXO

50 75 100 125 150

Temperature (∘C)

(b)

Hea

t flow

(ua

)

EXO

120 130 140 150 160

PLAO1

PLAO2

PLAO3

PLA

Temperature (∘C)

(c)



4 Conclusion



3000

2500

2000

1500

1000

500

05 10 15 20 25 30 35

Cou

nts

1

2

3

2120579 (∘)

(a)

3000

2500

2000

1500

1000

500

05 10 15 20 25 30 35

Cou

nts

1

2

3

2120579 (∘)

(b)

Cou

nts

1

2

3

5 10 15 20 25 30 35

2120579 (∘)

4000

3000

2000

1000

0

(c)

2000

1500

1000

500

05 10 15 20 25 30 35

Cou

nts

1

2

3

2120579 (∘)

(d)





Acknowledgments


References


























































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




0

5

10

15

20

25

0ndash10

10ndash3

0

30

ndash50

50

ndash70

70

ndash90

90

ndash110

110

ndash130

130

ndash150

150

ndash170

170

ndash190

190

ndash210

210

ndash230

230

ndash250

250

ndash270

270

ndash290

290

ndash310

310

ndash330

Con

tent

()

Diameter (nm)

(a)

0

5

10

15

20

25

Con

tent

()

0ndash10

10ndash3

0

30

ndash50

50

ndash70

70

ndash90

90

ndash110

110

ndash130

130

ndash150

150

ndash170

170

ndash190

190

ndash210

210

ndash230

230

ndash250

250

ndash270

270

ndash290

290

ndash310

310

ndash330

Diameter (nm)

(b)

0

5

10

15

20

25

Con

tent

()

0ndash10

10ndash3

0

30

ndash50

50

ndash70

70

ndash90

90

ndash110

110

ndash130

130

ndash150

150

ndash170

170

ndash190

190

ndash210

210

ndash230

230

ndash250

250

ndash270

270

ndash290

290

ndash310

310

ndash330

Diameter (nm)

(c)

0

5

10

15

20

25

Con

tent

()

0ndash10

10ndash3

0

30

ndash50

50

ndash70

70

ndash90

90

ndash110

110

ndash130

130

ndash150

150

ndash170

170

ndash190

190

ndash210

210

ndash230

230

ndash250

250

ndash270

270

ndash290

290

ndash310

310

ndash330

Diameter (nm)

(d)










1

(A) 119889

2

(A) 119889

3

(A) 119863

1

(nm) 119863

2

(nm) 119863

3


Hea

t flow

(ua

)

EXO

30 40 50 60 70 80

Temperature (∘C)

(a)

Hea

t flow

(ua

)

EXO

50 75 100 125 150

Temperature (∘C)

(b)

Hea

t flow

(ua

)

EXO

120 130 140 150 160

PLAO1

PLAO2

PLAO3

PLA

Temperature (∘C)

(c)



4 Conclusion



3000

2500

2000

1500

1000

500

05 10 15 20 25 30 35

Cou

nts

1

2

3

2120579 (∘)

(a)

3000

2500

2000

1500

1000

500

05 10 15 20 25 30 35

Cou

nts

1

2

3

2120579 (∘)

(b)

Cou

nts

1

2

3

5 10 15 20 25 30 35

2120579 (∘)

4000

3000

2000

1000

0

(c)

2000

1500

1000

500

05 10 15 20 25 30 35

Cou

nts

1

2

3

2120579 (∘)

(d)





Acknowledgments


References


























































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials






1

(A) 119889

2

(A) 119889

3

(A) 119863

1

(nm) 119863

2

(nm) 119863

3


Hea

t flow

(ua

)

EXO

30 40 50 60 70 80

Temperature (∘C)

(a)

Hea

t flow

(ua

)

EXO

50 75 100 125 150

Temperature (∘C)

(b)

Hea

t flow

(ua

)

EXO

120 130 140 150 160

PLAO1

PLAO2

PLAO3

PLA

Temperature (∘C)

(c)



4 Conclusion



3000

2500

2000

1500

1000

500

05 10 15 20 25 30 35

Cou

nts

1

2

3

2120579 (∘)

(a)

3000

2500

2000

1500

1000

500

05 10 15 20 25 30 35

Cou

nts

1

2

3

2120579 (∘)

(b)

Cou

nts

1

2

3

5 10 15 20 25 30 35

2120579 (∘)

4000

3000

2000

1000

0

(c)

2000

1500

1000

500

05 10 15 20 25 30 35

Cou

nts

1

2

3

2120579 (∘)

(d)





Acknowledgments


References


























































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




3000

2500

2000

1500

1000

500

05 10 15 20 25 30 35

Cou

nts

1

2

3

2120579 (∘)

(a)

3000

2500

2000

1500

1000

500

05 10 15 20 25 30 35

Cou

nts

1

2

3

2120579 (∘)

(b)

Cou

nts

1

2

3

5 10 15 20 25 30 35

2120579 (∘)

4000

3000

2000

1000

0

(c)

2000

1500

1000

500

05 10 15 20 25 30 35

Cou

nts

1

2

3

2120579 (∘)

(d)





Acknowledgments


References


























































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials

























































CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials

























CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials










CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials



Documents

Research Article Nanostructured Polylactic Acid/Candeia …downloads.hindawi.com/journals/jnm/2015/439253.pdf · 2019-07-31 · Research Article Nanostructured Polylactic Acid/Candeia