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Sugar Alcohol based Materials for Seasonal Storage Applications
FP7 project - SAM.SSA
Sugar Alcohol based Materials for Seasonal Storage Applications
Workshop and Onsite Demonstration– CiCenergigune
Miñano, Alava, Spain
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015
Microencapsulation of sugar alcohols by different chemical and physical procedures
Session 1, Sub Session: 2
Presented by: María Dolores Romero
AIDICO. Technological
Institute of Construction
Thomas Ballweg - FhG
María Dolores Romero - AIDICO
Contributions by:
Radu Piticescu – IMNR
Roxana Piticescu
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015
Microencapsulation of sugar alcohols by different chemical and physical procedures
OUTLINE
1. INTRODUCTION
2. MICROENCAPSULATION OF SA WITH ORGANIC SHELLS (AIDICO)
Microencapsulation techniques Main results Conclusions
3. MICROENCAPSULATION OF SA WITH INORGANIC SHELLS (IMNR)
Description of procedure for microencapsulation Main results Conclusions
4. ENCAPSULATION OF SA WITH HYBRID SHELLS (FhG)
Description of procedure for microencapsulation Main results Conclusions
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015 Source: BASF
Source: Cryopak website
1. INTRODUCTION
THERMAL ENERGY STORAGE
Thermal Chemical
Sensible heat
Liquids Solids
Latent heat
Solid-liquid Liquid-gaseous Solid-solid
Heat reaction
Heat pumps
PCMs
AB + Q A + B
A + B AB + Q Amount of stored heat
Te
mpera
ture
Phase change
temperature
Latent heat of the
phase change
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015 Source: BASF
Source: PPL products
1. INTRODUCTION
PCM: Phase change material
Substance able to absorb, store and release energy during the phase change
High latent heat
Chemically: paraffin wax, ester, fatty acid, hydrated salt
Source: BASF website
PCM: Latent heat storage
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015
Limitations of PCMs
Dimensional instability
Corrosiveness
Low thermal conductivity
Compatibility with other materials
Encapsulation
Substances (core materials) introduced in a
matrix or shell
Macroencapsulation Microencapsulation
Nanoencapsulation
Source: BASF
PCMs in containers (cm)
Leakage
Source: PPL products website
1. INTRODUCTION
PCM: Phase change material
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015 Source: BASF Source: Cryopak website
Microencapsulation of PCMs
1. INTRODUCTION
Thermal properties
Proper phase change temperature
High latent heat storage
Proper thermal conductivity (depending on application)
Physical properties Small volume change during phase change process
Low vapor pressure
Kinetics Proper subcooling (depending on application)
Crystallization process
Chemical properties
Long term chemical stability
Compatible with container (corrosion)
No toxicity
No fire risk
Economics Available in the market
Cost effective for large scale production
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015
Source: BASF
Microencapsulation of PCMs
1. INTRODUCTION
Physico-chemical processes
Mechanical processes
Chemical processes
Particle size, physico-chemical properties of core and shell materials
Microencapsulation techniques
Microparticles
Membrane Internal phase
Microcapsules
Active principle
Microspheres
Matrix
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015
PCMs: Selection of Sugar Alcohol
Specifications of Sugar Alcohols :
Sugar Alcohol Melting point (ºC) Latent heat
(KJ/Kg)
Density (Kg/m3) Specific heat (KJ/Kg K)
Liquid Solid Liquid Solid
Erythritola 118 354.7 1280 1450 2.66 1.68
Dulcitolb 168-169 401 -- 1466 -- 1.31
D-Mannitolc 165.0 () 338 () -- -- -- --
Xylitold 93.20 301.12 -- -- -- --
a T. Oya et al. Applied Thermal Engineering 40 (2012) 373-377. b A. Sari et al. Solar Energy 85 (2011) 2061-2071. c C. Telang et al. Pharmaceutical Research 20 (2003) 1939-1945. d A. Biçer, A. Sari Solar Energy Materials & Solar Cells 102 (2012) 125-130.
1. INTRODUCTION
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015
Reactivity of hydroxyl group
Disadvantage of Sugar Alcohols for microencapsulation:
C CR O
H+ +
+
-
Nucleophilic Site
Electrophilic Site
Selection of microencapsulation methodology
Selection of shell
1. INTRODUCTION
Organic Hybrid Inorganic
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015
Solvent evaporation
The size of nanoparticles can be controlled by adjusting:
Stirring rate
Type and amount of dispersing agent Viscosity of organic and aqueous phases
Temperature
Evaporation rate
Emulsification Solvent evaporation
S u r f a c t a n t O i l p h a s e
R O H
S u r f a c t a n t P o l y m e r
S o l v e n t
E v a p o r a t i o n P o l y m e r
W a t e r
Sugar Alcohol
2. MICROENCAPSULATION OF SA WITH ORGANIC SHELLS
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015
D-Mannitol/PMMA
Surfactant concentration (1, 3, 5% Span80)
Type of surfactant
Xylitol, dulcitol, erythritol
Solvent evaporation
Solvent/non solvent
H2O
Sugar alcoholPolymer Surfactant
non solvent
n
O O
PMMA
HO
OH
OH
OH
OH
OH
D-Mannitol
Solvent evaporation
2. MICROENCAPSULATION OF SA WITH ORGANIC SHELLS
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015
DSC
Sample Tm (ºC) ΔHm (J/g) Tc (ºC) ΔHc (J/g)
Mannitol 166 260.1 113.7 194.6
1% 159.7 78.6 99.2 48.0
3% 157.7 88.5 102.5 40.7
5% 155.6 178.3 105.6 140.8
vs
Tm D-Mannitol
Tm α (ºC) 165.5
Tm β (ºC) 165.0
Tm δ (ºC) 155
Tg (ºC) 10.7
Telang et al.
Pharmaceutical
Research, 2003,
20, 1939-1945
D-Mannitol/PMMA
Amount of oil phase surfactant
Solvent evaporation
2. MICROENCAPSULATION OF SA WITH ORGANIC SHELLS
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015
1% Oil phase surfactant
5% Oil phase surfactant
3% Oil phase surfactant
Amount of oil phase surfactant
Solvent evaporation
2. MICROENCAPSULATION OF SA WITH ORGANIC SHELLS
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015
Oil phase Oil phase
Hydrophilic monomer M1
H2O
Hydrophilic compounds Sugar alcohol
Addition of M2
Crosslinking reaction at the interface
NR'
NC CO O
OHR
HO
NH2R
H2N
or CO
RO
C
HN
R'
HN
C
OOO n
or C
HN
R
HN
C
HN
R'
HN
C
OOO n
Polyurethane Polyurea M1
M2
Interfacial polycondensation
2. MICROENCAPSULATION OF SA WITH ORGANIC SHELLS
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015
1, 3 and 5 wt%
Surfactant: Lubrizol Amino-functionalized
Able to react with TDI
Type of isocianate
Type and amount of surfactant (-NH or –OH functionalities)
Isocianate/ROH ratio
Microcapsules properties (size, morphology, etc.) depend on:
Interfacial polycondensation
2. MICROENCAPSULATION OF SA WITH ORGANIC SHELLS
NCO
NCO
HO
OH OH
OH
D-MannitolTDI
OH
OH
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015
D-Mannitol microspheres
5% surfactant
Interfacial polycondensation
2. MICROENCAPSULATION OF SA WITH ORGANIC SHELLS
3% surfactant
ROH/TDI = 1/1
1% surfactant
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015
D-Mannitol
microspheres 0.5
1.0
T
5% 0.5
T
3% 0.5
1.0
T
1% 0.5
1.0
T
TDI
60
80 100
T
2000 Wavenumber (cm-1)
ROH/TDI = 1/1 Surfactant concentration
Interfacial polycondensation
2. MICROENCAPSULATION OF SA WITH ORGANIC SHELLS
-4
-3
-2
-1
0
1
2
3
4
20 40 60 80 100 120 140 160 180 200
Hea
t F
low
(J/
g)
Temperature (ºC)
5% surfactant
3% surfactant
1% surfactant
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015
AIR NITROGEN
-10
-5
0
5
10
15
20
20 40 60 80 100 120 140 160 180 200
Hea
t flow
(W
/g)
Temperature (ºC)
D-Mannitol - Cycle 1 - N2
D-Mannitol - Cycle 30 - N2
5% surfactant - Cycle 1 - N2
5% surfactant - Cycle 30 - N2
-15
-10
-5
0
5
10
15
20
25
20 40 60 80 100 120 140 160 180 200
Hea
t flow
(W
/g)
Temperature (ºC)
D-Mannitol - Cycle 1-AIR
D-Mannitol - Cycle 30 - AIR
5% Surfactant - Cycle 1 - AIR
5% surfactant - Cycle 30 - AIR
Interfacial polycondensation
2. MICROENCAPSULATION OF SA WITH ORGANIC SHELLS
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015
The decrease of thermal energy storage capacity is not only due to the oxidation by the air, but also the temperature increase in thermal cycles, which favors the reaction between the prepolymer and the sugar alcohol: -OH of the SA react with the polymer when increasing temperature during thermal cycles
This effect has been produced both in D-Mannitol and Erythritol, which have different melting and crystallization temperatures and also different chemical structure and number of –OH groups
Although it is possible to obtain sugar alcohols microcapsules by interfacial polycondensation, thermal stability of the capsules during thermal cycling can be improved by studying how to finish the reaction of the prepolymer
Polyurethane and polyurea bonds can be formed between the –OH or –NH2 of the surfactant and the isocianate
-OH containing surfactant is not a good solution (reaction between isocianate and D-Mannitol is also produced). A different surfactant with different chemical groups, competing with –OH from sugar alcohol is required to react with TDI
Interfacial polycondensation - Conclusions
2. MICROENCAPSULATION OF SA WITH ORGANIC SHELLS
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015
SOL-GEL
3. MICROENCAPSULATION OF SA WITH INORGANIC SHELLS
• SiO2 as TEOS. Mannitol in spheres from spray drying
D-Mannitol in benzyl alcohol
TEOS SiO2 as TEOS
D-Mannitol as spheres from spray drying (not dissolution, but dispersion)
Water-free process. Hydrolysis of TEOS with benzyl alcohol
D-Mannitol : TEOS = 1 : 1 and 1 : 3 (wt)
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015
SOL-GEL
3. MICROENCAPSULATION OF SA WITH INORGANIC SHELLS
• SiO2 as TEOS. Mannitol in spheres from spray drying
632
700 888
1019
1086
1287 1424
1641
D-Mannitol from spray drying
2909
2970
3284
0.0
0.5
1.0
1.5
Abs
700
732 1007
1086
1208
1451
1496 2871
3029
3302
Encapsulations with SiO2
-0.00
0.02
0.04
0.06
0.08
0.10
Abs
2000
Wavenumber (cm-1)
D-Mannitol
SiO2
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015
SOL-GEL
3. MICROENCAPSULATION OF SA WITH INORGANIC SHELLS
D-Mannitol from spray drying
Encapsulations with SiO2
• SiO2 as TEOS. Mannitol in spheres from spray drying
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015
SOL-GEL
3. MICROENCAPSULATION OF SA WITH INORGANIC SHELLS
-10
-5
0
5
10
15
20
25
30
0 50 100 150 200
He
at f
low
(W
/g)
Temperature (ºC)
D-Mannitol Spray drying
D-Mannitol:TEOS = 1:1 (wt)
D-Mannitol:TEOS = 1:3 (wt)
DSC – air atmosphere
Tm (ºC) ΔHm (J/g) Tc (ºC) ΔHc (J/g)
D-Mannitol spray drying
167.0 260.9 117.6 204.0
Encapsulation with SiO2 (1:1)
163.6 67.6 106.5 57.7
Encapsulation with SiO2 (1:3)
163.8 84.9 107.9 70.6
• SiO2 as TEOS. Mannitol in spheres from spray drying
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015
SOL-GEL
3. MICROENCAPSULATION OF SA WITH INORGANIC SHELLS
• SiO2 as TEOS. Mannitol in spheres from spray drying
-3
-2
-1
0
1
2
3
4
5
0 20 40 60 80 100 120 140 160 180 200
He
at flo
w (
W/g
)
Temperature (ºC)
Cycle 1. Melting
Cycle 1. Crystallization
Cycle 10. Melting
Cycle 10. Crystallization
Cycle 20. Melting
Cycle 20. Crystallization
Cycle 30. Melting
Cycle 30. Crystallization
Mannitol:TEOS = 1:1
-4
-2
0
2
4
6
8
0 20 40 60 80 100 120 140 160 180 200
He
at flo
w (
W/g
)
Temperature (ºC)
Cycle 1. Melting
Cycle 1. Crystallization
Cycle 10. Melting
Cycle 10. Crystallization
Cycle 20. Melting
Cycle 20. Crystallization
Cycle 30. Melting
Cycle 30. Crystallization
Mannitol:TEOS = 1:3
Thermal cycle 1 Thermal cycle 30
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015
SOL-GEL
3. MICROENCAPSULATION OF SA WITH INORGANIC SHELLS
a)
b) c)
• SiO2 as TEOS. Mannitol in spheres from spray drying
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015
SOL-GEL
3. MICROENCAPSULATION OF SA WITH INORGANIC SHELLS
D-Mannitol (spheres from spray drying)
Benzyl alcohol
Ti precursor
-OH groups
-OH groups Hydrolysis of Ti
Orange solution: Ti compounds
- TiO2 . Mannitol dispersed in organic solvent: avoid water
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015
SOL-GEL
3. MICROENCAPSULATION OF SA WITH INORGANIC SHELLS
Tm (ºC) ΔHm (J/g) Tc (ºC) ΔHc (J/g)
D-Mannitol 166.0 260.1 113.7 194.6
Encapsulation with TiO2
166.4 239.0 120.4 179.9
DSC – air atmosphere
-15
-10
-5
0
5
10
15
20
25
0 50 100 150 200
He
at f
low
(W
/g)
Temperature (ºC)
Heating D-Mannitol
Cooling D-Mannitol
Heating - Encapsulation with TiO2
Cooling - Encapsulation with TiO2
- TiO2 . Mannitol dispersed in organic solvent: avoid water
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015
SOL-GEL
3. MICROENCAPSULATION OF SA WITH INORGANIC SHELLS
-10
-5
0
5
10
15
20
25
0 50 100 150 200
He
at f
low
(W
/g)
Temperature (ºC)
D-Mannitol - Cycle 1 - N2
D-Mannitol - Cycle 30 - N2
Encapsulation - Cycle 1 - N2
Encapsulation - Cycle 30 - N2
Tm (ºC) ΔHm (J/g) Tc (ºC) ΔHc (J/g)
Cycle 1 165.2 202.0 112.7 106.2
Cycle 30 165.6 202.1 115.1 152.6
Tm (ºC) ΔHm (J/g) Tc (ºC) ΔHc (J/g)
Cycle 1 166.0 209.9 120.7 157.4
Cycle 30 166.6 195.5 124.4 161.6
D-Mannitol
Encapsulations with TiO2
- TiO2 . Mannitol dispersed in organic solvent: avoid water
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015
SOL-GEL
3. MICROENCAPSULATION OF SA WITH INORGANIC SHELLS
- TiO2 . Mannitol dispersed in organic solvent: avoid water
Tª = 30 ºC Tª = 105 ºC Tª = 160 ºC
Tª = 167 ºC Tª = 183 ºC Tª = 30 ºC
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015
SOL-GEL
3. MICROENCAPSULATION OF SA WITH INORGANIC SHELLS
CONCLUSIONS
SiO2
TiO2
- Water free process required
- By using aqueous solutions of Mannitol, hydrolysis of TiO2 is produced, but Mannitol is removed with the aqueous phase
- Possible procedure for encapsulations with TiO2 (heat storage capacity, subcooling, durability under thermal cycles).
Deeper analysis is being currently done.
- SiO2 particles do not anchor with the D-Mannitol, as the sugar alcohol stays with the aqueous phase
- Hydrolysis of SiO2 has to be done in water-free process
- Microencapsulation of D-Mannitol seems to be suitable by sol-gel procedures in water-free processes
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015
3. MICROENCAPSULATION OF SA WITH INORGANIC SHELLS
Elaboration of a hydrothermal /solvothermal process to encapsulate sugar alcohols
in zinc oxide shell as an alternative to the chemical process of simple or complex coacervation
Investigate the influence of pressure on the formation of ZnO-sugar alcohols
composites (crystal growth process, crystallisation, crystal shape and morphology)
OBJECTIVES
HYDROTHERMAL / SOLVOTHERMAL
Preparation and characterization of core/shell structures based on mannitol and ZnO
Mathematical model of ZnO-Mannitol hydrothermal synthesis process at high pressures
Preparation and characterization of core/shell structures based on erythritol and ZnO
RESULTS
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015
3. MICROENCAPSULATION OF SA WITH INORGANIC SHELLS
Characterization methods: - Chemical analysis: ICP-OES (Agilent
Technology) - Particle sizes, Zeta Potential:
Malvern ZS 90 - XRD (Brucker D8 Advance) - FT-IR (ABB) - SEM: HITACHI S2600N (Centre 3MN) - Thermal analysis: DSC Netzch F3 Maya DSC-TG Setsys Setaram
Water soluble Zn salt Spray dried S.A.
S-A encapsulated in ZnO nanomatrices
Synthesis pressure: 100 – 3000 bar T < 100 deg.C
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015
3. MICROENCAPSULATION OF SA WITH INORGANIC SHELLS
Micro-encapsulation of D-Mannitol in ZnO nanomatrices
DSC-TG curve for ZnO M8-1 (ZnO : mannitol =10:1), P=100 bar
SEM of ZnO 10:1
(P=100 bar)
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015
3. MICROENCAPSULATION OF SA WITH INORGANIC SHELLS
Micro-encapsulation of D-Mannitol in ZnO nanomatrices
DSC-TG curve for ZnO : mannitol = 4:1, P=1000 bar
SEM ZnO :Mannitol 4:1, P=1000 bar)
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015
3. MICROENCAPSULATION OF SA WITH INORGANIC SHELLS
Micro-encapsulation of D-Mannitol in ZnO nanomatrices
FT-IR spectra for ZnO : mannitol = 4:1, P=1000 bar
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015
3. MICROENCAPSULATION OF SA WITH INORGANIC SHELLS
Micro-encapsulation of D-Mannitol in ZnO nanomatrices
DSC-TG curve and SEM for ZnO : mannitol = 4:1, P=3000 bar
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015
3. MICROENCAPSULATION OF SA WITH INORGANIC SHELLS
Micro-encapsulation of D-Mannitol in ZnO nanomatrices
FT-IR curve for ZnO : mannitol = 4:1, P=3000 bar
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015
3. MICROENCAPSULATION OF SA WITH INORGANIC SHELLS
Micro-encapsulation of Erythritol in ZnO nanomatrices
4000 3500 3000 2500 2000 1500 1000 500
10
20
30
40
50
60
70
80
90
100
T [
%]
Wavenumber [cm-1]
erythritol
ZnO-Er2
FT-IR of ZnO-Er2 sample
(ZnO:erythritol=4:1,100 atm.)
SEM of ZnO-Er2 sample
(ZnO:erythritol=4:1, 100 atm.)
Succesful encapsulation clear observed.
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015
3. MICROENCAPSULATION OF SA WITH INORGANIC SHELLS
Innovation with respect to the state of the art: Hydrothermal / solvothermal process is used to encapsulate sugar alcohols (D-
mannitol and Erythritol) in ZnO shell as an alternative to the chemical process of simple or complex coacervation.
Hydrothermal / solvothermal synthesis advantages: the possibility to work at low
temperatures (<1000 C) and high pressures ( 100-3000 atm), single, one step process, controlled composition, morphology and microstructure.
ZnO – nano was selected due to its versatility and compatibility with SA (in particular D-mannitol or erythritol)
Modelling of the encapsulation process of mannitol in ZnO shell by hydrothermal
process at pressures between 100 and 3000 atm, revealed that 1000 atm is enough for obtaining a good encapsulation degree.
Improved handling and good thermal stability in the final product expected.
CONCLUSIONS
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015
Participants: Thomas Ballweg, Doris Hanselmann
Encapsulation by Way of UV-curable Hybridpolymeric and Monomeric Building Blocks
Principle
• Vibration assisted microdrop generation through a concentric nozzle combination
• „Cold“ UV-curing with short residence time in the radiation field ( < 1/10 s)
• Encapsulation of sugar alcohol supersaturated aqueous solutions or sugar alcohol melts collector
UV-curing
shell material core material
ring nozzle
Scheme of the encapsulation process
4. ENCAPSULATION OF SA WITH HYBRID POLYMERS
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015
General Properties
• Capsules size range: 0.5 – 5 mm
• Adjustable wall thickness
• Monomodal size distribution
• Core-shell-type morphology
• Transparency of the shell allowing the visual control of the physical condition of the sugar alcohol
High speed photographs of the encapsulation process showing the vibration assisted drop
generation
Encapsulation by Way of UV-curable Hybridpolymeric and Monomeric Building Blocks
4. ENCAPSULATION OF SA WITH HYBRID POLYMERS
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015
Capsule Quality and Wall Thickness Control
High capsule quality and good wall thickness control attainable
Core:Shell ratio = 5:1 Core:Shell ratio = 2:1
4. ENCAPSULATION OF SA WITH HYBRID POLYMERS
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015
Monomeric Di- and Trifunctional Monomeric and Hybrid Polymeric Building Blocks for High Strength Shells
Trimethacrylato- (3-mercaptopropyl)methyldimethoxysilane
Trimethylpropanetriacrylate (TMPTA)
Urethanedioldimethacrylate (UDMA)
4. ENCAPSULATION OF SA WITH HYBRID POLYMERS
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015
Encapsulation of Xylitol-Erythritol Eutectic Melt by 2-Stage Curing
Xylitol-Erythritol-filled Capsules before and after crystallisation
Process-related challenges solved by means of 2-stage curing of
acrylate-methacrylate based shell material combinations
4. ENCAPSULATION OF SA WITH HYBRID POLYMERS
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015
On the Destructive Power of Sugar Alcohol Crystallisation
Images: © Fraunhofer
Typical crystallisation-induced defects
• Process-related challenges solved…., but crystallization-related challenges remained
• 5 MPa uniaxial pressure resistance isn’t enough to withstand crystallization forces
ca. 5 MPa
(50 bar)
4. ENCAPSULATION OF SA WITH HYBRID POLYMERS
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015
Elastomeric Shell Material Alternatives for Sugar Alcohol Encapsulation
Capsule Size: 3,0 0,1 mm Compr. Strength: 20,7 2,1 N Deform. at break: 54,5 1,5 %
Composition:
4. ENCAPSULATION OF SA WITH HYBRID POLYMERS
1 : 2
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015
• Gas bubbles
Motivation:
• MASA-modifications for short time cycling (day-night) application
• Running MASA-PCMs in the not-subcooling mode
Results:
• Integration of encapsulation-compatible trigger mechanisms possible
• Low acceleration of crystallization
• Solvents • Particles
Integration of Nucleation Promoters
4. ENCAPSULATION OF SA WITH HYBRID POLYMERS
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015
Conclusions and Outlook
• Encapsulation of sugar alcohols melts by means of vibration assisted microdrop generation and UV-curing successfully realized
• Capsule size in the mm-range complementary to true microencapsulation
• Monomodal size distribution with controllable wall thickness
• Core-shell-type morphology
• Building blocks for high strength and flexible elastomeric shells applicable
• Integration of nucleating agents (particles, solvents, gas bubbles) demonstrated
Outlook
• Optimization of thermo-chemical & mechanical stability at cycling
• Further development of nucleation agents for promoting short time cycling
• Increase of the processing temperature beyond 120 °C
4. ENCAPSULATION OF SA WITH HYBRID POLYMERS
Workshop and Onsite Demonstration ● CiCenergigune, Spain ● March 17/18, 2015
The SAM.SSA project The SAM.SSA project
Thank you very much for your attention