Journal of Materials Sciences and Applications

2015; 1(4): 136-141

Published online July 20, 2015 (http://www.aascit.org/journal/jmsa)

Keywords Polyvinyl Chloride,

Thermoplastic Polyurethane,

Transparency,

Cold Resistance

Received: June 16, 2015

Revised: June 29, 2015

Accepted: June 30, 2015

The Effect of TPU on Properties of Polyvinyl Chloride

Yapeng Li1, Xuejia Ding

1, Hanqing Gu

2, Guoying Hu

2

1Beijing Laboratory of Biomedical Materials, Beijing University of Chemical Technology, Beijing,

China 2Tianjin Institute of Urology, Tianjin Medical University, Tianjin, China

Email address dingxj2011@126.com (Xuejia Ding)

Citation Yapeng Li, Xuejia Ding, Hanqing Gu, Guoying Hu. The Effect of TPU on Properties of Polyvinyl

Chloride. Journal of Materials Sciences and Applications. Vol. 1, No. 4, 2015, pp. 136-141.

Abstract In this work, fracture toughness and properties of blends of plasticized polyvinyl

chloride (PVC) and three kinds of thermoplastic polyurethane (TPU) were investigated.

The blending between the two was in the Two-roll Mill. The effects of different content

of TPU on the transparency, mechanical properties, hardness were investigated, we also

researched the low temperature (-23°C) impact strength, scanning electron microscope

(SEM) and thermo gravimetric analyzer (TGA). With the constant of TPU increasing, the

low temperature impact strength of PVC increased, while hardness decreased. It was

indicated that the PVC/TPU blends had good transparency by transmittance and haze

testing, and thermal stability was tested with thermo gravimetric analyze. TPU can

decrease the tensile strength of PVC, and increase the elongation at break of it. We

probably indicated that the fracture of PVC/TPU blends is ductile fracture from SEM.

1. Introduction

Poly (vinyl chloride) (PVC) plays an important role in the plastic industry and it is one

of the most versatile thermoplastics of the world, PVC is a commodity plastic with many

good properties, such as excellent flame retardant properties, great wear resistance,

chemical resistance and good transparency. In addition, mechanical and electrical

insulating properties of PVC are also wally. It has been widely used in construction,

furniture and other fields. The impact performance of PVC is poor especially at low

temperatures, with the temperature of the product decreasing quickly, PVC becomes

brittle and prone to brittle fracture. In order to improve or overcome these shortcomings,

enhance the comprehensive properties, endow with new functions, and expand the PVC

applications, it must be combined with a number of additives before processing.

Thermoplastic polyurethane (TPU) is one of the most versatile products in the group

of engineering thermoplastics with elastomeric properties. TPUs are characterized by a

two-phase morphology in which a soft phase is reinforced by condensation with a hard

domain consisting of an aromatic diisocyanate extended with a short-chain diol. Soft

segments which are quite mobile and normally present in coiled formation, alternate with

stiff oligourethane units, so it is called hard segments[1-2]

.TPU is widely used in mining,

construction, automotive, footwear and machinery.

With the blending of PVC and TPU, TPU which plays a plasticizing effect can

toughen PVC, moreover, it can also improve its liquidity. PVC blends with the small

amount of TPU, which not only reduce the cost of TPU, but also achieve the purpose of

the modification of PVC [3]

.

Hu Wentao[4]

have studied the performance influence between polyvinyl chloride and

thermoplastic polyurethane. The effects of different content of TPU (polyester type and

137 Yapeng Li et al.: The Effect of TPU on Properties of Polyvinyl Chloride

polyether type) on the transparency, mechanical properties

and the low temperature impact strength were investigated

systematically. The results showed that adding an appropriate

amount of the polyurethane does not affect the transparency

of the PVC, but polyurethane can significantly improve the

cold resistance of polyvinyl chloride and reduce the

temperature of Tg.

Ye Chengbing[5]

have researched that how to prepare

PVC/TPU blends system by mechanical blending. He

focused on the mechanical properties, low temperature

properties and thermal stability, etc. The result showed that

PVC/TPU blends have synergistic effect on the mechanical

properties, and the blends can improve the tensile strength,

the low temperature impact strength and the thermal stability

of PVC.

2. Experimental

2.1. Materials

PVC (SG-65) was from Formosa Plastics Industry (Ningbo)

Co, Ltd. DINCH was supplied by BASY as Plasticizer. Three

polyether type TPUs (1085A, ER-80A and Bayer 60A) were

kindly provided by Shanghai Lubrizol Ltd (China), Gaoding

Chemical Company (Taiwan) and Bayer (Germany). The

differences in hardness arise from different ratios of hard to

soft segments, which in turn leads to different soft segment

molecular weights. The Ca/Zn composite stabilizer were

obtained from Bayer polyurethane Co. LTD, Shanghai, China.

2.2. Sample Preparation

According to a certain proportion (shown in table 1), PVC,

DINCH plasticizer, Ca/Zn composite stabilizer and a variety

of auxiliary additives were mixed in a high speed mixer,

followed at low-speed and then high-speed as for as the

temperature reached at 110°C. The resultant mixture was

poured immediately into the cooled mixed with stirring until

the mixture temperature dropped to 60°C. The mixture was

prepared in the Two-roll Mill(XH-401B,Xihua sophisticated

testing equipment company, China) at 165°C for 10min after

adding to TPU.

The resultant mixture was immediately put into a mold of

Pressure Machine (XH-406,Xihua sophisticated testing

equipment company, China) to produce plate PVC pieces at

180°C for 10min, during the hot 5min and the cold 5min.

Different test samples of specific shapes were cut by a cutting

machine after standing at room temperature for 24 hours.

Table 1. Heat Deflection Temperature of the blends.

Material Dosage/phr①①①①

PVC 100

DINCH 30

ESO 3

Ca/Zn composite stabilizer 2

TPU 3-15

①The dosages of all ingredients are expressed in parts by weight.

2.3. Measurement

2.3.1. Mechanical Testing

Tensile strength tests were performed according to

GB/T1040.1-2006 with a electronic universal testing

machine (AMETEK LR30K, Britain). Five or more

specimens per material were tested and the mean value of

each item was determined. The distance between points was

defined as 60mm, and the drawing speed was defined as

50mm/min to obtain stress-strain curves.

2.3.2. Impact Testing

Izod impact strength was measured by using an Izod

impact tester (Ceast Co., Italy) at the low temperature

(-23°C). according to Chinese standard GB/T1843–2008.The

samples were fractured in liquid nitrogen for 5min and then

removed and tested. The sample size was 80mm × 10mm × 2

mm. Five measurements were averaged.

2.3.3. Scanning Electron Microscopy (SEM)

The morphology of various PVC samples were observed

by using a JSM-6700F scanning electron microscope (SEM),

at an accelerate voltage of 10KV. The samples were

cryogenically fractured in liquid nitrogen. The surface of the

samples used for SEM was gold-sputtered with a conductive

layer before observation.

2.3.4. Thermo Gravimetric Analyzer (TGA)

Thermo gravimetric analysis (TGA) was performed on

TGA Q500 (TA) apparatus to investigate the thermal

decomposition of the PVC/TPU blends under N2 atmosphere.

Samples of 5 mg were heated from 40°C up to 600°C with

heating rate of 10°C/min.

2.3.5. Differential Scanning Calorimeter

(DSC)

The glass transition temperature (Tg) was determined

using the differential scanning calorimeter (DSC) performed

on a DSC Q500. The temperature program was between

-80 °C and 100 °C at a rate of 3 °C·min-1

. The sample mass

was 3 mg.

Figure 1. Effect of TPU content on transmittance.

Journal of Materials Sciences and Applications 2015; 1(4): 136-141 138

Figure 2. Effect of TPU content on haze.

3. Results and Discussion

3.1. Effect of TPU Content on Transparence

Figure 1 showed that the effect of TPU content on

transmittance. With the addition of TPU, the transmittance of

three PVC/TPU blends was gradually reduced. Moreover, the

transmittance of PVC/ER-80A blends was higher than

PVC/1085A and PVC/Bayer 60A obviously. In Figure 2, the

haze of three blends initially increased until increasing

amount of TPU up to 15 phr. What is more, the increasing of

haze when use 1085A was more than that when use the same

amount of ER-80A or Bayer 60A as compatibilizer. This

could be due to the TPU was dispersed in PVC and existed

the phase interface between two phases. when lights reflected

off phase interface, it happened to scatter.

In summary, the transparence of PVC/ER-80A blends was

excellent, followed by PVC/Bayer 60A blends, PVC/1085A

blends were the worst. When add amount of ER-80A was up

to 5 phr, the haze of PVC increased 40.3%, and the

transmittance decreased 4.6%. This because the ER-80A and

PVC has almost the same refractive index[6]

.

Figure 3. Tensile strength of PVC/TPU blends.

Figure 4. Elongation at break of PVC/TPU blends.

3.2. Effect of TPU Content on Mechanical

Property

The stress–strain results of PVC, and PVC/TPU blends

were presented in Figure 3 and Figure 4.The tensile strength

of PVC/ER-80A and PVC/Bayer 60A blends were

significantly decreased with the increase of TPU contents.

The tensile strength of blends modified with PVC/Bayer 60A

decreases less than that with PVC/ER-80A when increase the

amount of TPU. However, PVC/1085A blends were the first

increased and then decreased with the increase of TPU and

reached the maximum at 5 phr.

The elongation at break of PVC/1085A and PVC/Bayer

60A blends increased with the increasing of TPU contents.

Whereas, PVC/ER-80A blends were the growth before they

are reduced, with the increase of TPU and reached the

maximum at 7 phr.

One reason was that the TPU dispersed in PVC uniformly

and had toughened phenomenon, the other reason was the

TPU had a lower strength and higher elongation at break,

both the performance superimposed in accordance with a

certain proportion, the performance of the blend elongation at

break was improved but the tensile strength decreased[7]

.

3.3. Effect of TPU Content on Hardness

Table 2. Hardness of PVC/TPU blends.

content/

phr 0 3 5 7 10 15

Hardness/

shore D

1085A 75 74.5 74 74.2 72 72.7

ER-80A 75 74.5 72.7 72.2 72.5 72.1

Bayer

60A 75 72.8 72 71 71.5 71

The effects of hardness of PVC/TPU blends were given in

Table 2, with the addition of these three kinds of TPU, the

hardness of PVC/TPU blends were all decreased, but the

decline was not obvious, it is means that the content of TPU

was not much more impact. It might be that the hardness of

TPU was less than PVC[8]

, the hardness of PVC was shore D,

however, TPU’s hardness was shore A.

139 Yapeng Li et al.: The Effect of TPU on Properties of Polyvinyl Chloride

3.4. Effect of TPU Content on Cold

Resistance

In Figure 5, the Izod impact strength was plotted as a

function of temperature for the different PVC/TPU blends. It

was found that the low temperature impact strength of the

blends initially increased with increasing amount of TPU.

Moreover, the increasing of the impact strength of all

PVC/TPU blends when used 1085A and Bayer 60A was

more than that when using the same amount of ER-80A,

therefore ER-80A was relatively increased slowly. For

PVC/1085A, PVC/Bayer 60A and PVC/ER-80A blends the

maximum impact strength occurred when using 15 phr with

values of 43.2 KJ•m-2，42.3KJ•m

-2 and 36.0KJ•m

-2, which

increased about 32.5 percent,30.0 percent and 10.5 percent.

Figure 5. Low temperature impact strength of PVC/TPU blends.

When Thermoplastic elastomer subjected to external

forces, it would produce a large number of shear bands and

crazes around. Accompanied by shear bands and crazes,

external energy was absorbed. Additionally, the deformation

of TPU needed to absorb energy, too. Therefore, low

temperature impact strength was improved [9-10]

.

DSC curves were shown to judge the compatibility of

PVC/TPU blends in Figure 6. With the addition of TPU, the

Tg of the blends decreased evidently. It turned out that

adding TPU can improve cold resistance of PVC. Tg of Pure

PVC was -26.4 °C, and when the content of TPU was 15phr,

the blends (PVC/1085A, PVC/ER-80A,PVC/Bayer 60A)

decreased -39.43°C, -34.17°C and -40.24°C.

3.5. Effect of TPU Content on Thermal

Decomposition

TGA of PVC/TPU was shown in Table 3 and Figure 7

when adding TPU was 5 phr. Two-step degradation curves

(Figure 7) were observed for pure PVC and PVC/TPU blends,

which were completely degraded around 500 °C. The first

and second step of TPU decomposition was corresponding to

the breaking of urethane bond and the decomposition of

polyol. PVC samples exhibited two-step decomposition

process as well. And the first and the second step of PVC

decomposition were corresponding to the breaking of –C–

Cl– segment and the decomposition of –CH2– segment[11]

.

The thermal gravimetric graphs demonstrated that blends

with TPU (or without TPU) nearly had the same

decomposition temperature. So, the addition of TPU had little

effect on thermal stability of the PVC/TPU blends[12]

.

Figure 6. Tg of PVC/TPU blends.

Figure 7. TGA curves of PVC/TPU in N2 atmosphere.

Table 3. Thermal analysis of PVC/TPU blends.

Material T1wt%/°C Mass Loss I Mass Loss II

T50wt%/°C Tonset1/°C ML1/% Tonset2/°C ML2/%

PVC 199.97 264.96 65.85 447.74 16.98 292.73

1085A (5) 183.30 269.44 68.42 440.76 19.71 300.36

ER-80A (5) 208.65 260.01 66.79 438.63 18.12 290.72

Bayer 60A(5) 204.14 259.31 68.88 429.80 20.55 301.82

Journal of Materials Sciences and Applications 2015; 1(4): 136-141 140

Figure 8. SEM photographs of PVC/TPU blends section.

3.6. Effect of TPU Content on Scanning

Electron Microscope

Figure 8 was four scanning electron micrograph

photographs when adding TPU of 5 phr and without TPU.

The SEM photographs of the fracture surfaces of PVC and

PVC/TPU blends did show us that there were more large

cracks in PVC than in PVC/TPU blends. When TPU was 0

phr, the section of PVC was smooth belonging to brittle

fracture. With the content of TPU increasing, the section

became rough[13]

. This phenomenon is in agreement with the

impact strength result of Figure 5. It turns out that adding

TPU could make PVC ductile fracture, and so PVC could be

toughened by TPU.

4. Conclusion

First of all, the blending of PVC/TPU is premised on the

transparency, in the next place, the low temperature impact

strength of blending is improved as far as possible. By all

accounts, Bayer 60A is the best effect of materials

modification.

When adding amount of Bayer 60A was up to 5 phr, the

transmittance decreased 10.6% and the haze of PVC

increased 67.4%.with the improvement of the content of TPU,

the low-temperature impact strength and elongation at break

increased, tensile strength decreased yet. The tensile strength

decrease from 25.3MPa to 22.0 MPa, the elongation at break

increased from 256% to 282% and the low-temperature

impact strength increased from 32.6 KJ/m2to 42.3 KJ/m

2,The

addition of TPU had hardly any effect on thermal stability of

the PVC/TPU blends on thermo gravimetric analyzer as a

result of the initial extension temperature of PVC/TPU is

closed to pure PVC.SEM results indicated that the fracture of

PVC/TPU blends was ductile fracture.

Acknowledgments

The authors thank the National Science and Technology

Support Program (2012BAI22B07) for financial support.

141 Yapeng Li et al.: The Effect of TPU on Properties of Polyvinyl Chloride

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