The Effect of Polystyrene on the Crystallization of Poly(3-hydroxybutyrate)

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DOI: http://dx.doi.org/10.1590/1516-1439.242213

The Effect of Polystyrene on the Crystallization of Poly(3-hydroxybutyrate)

_Renate Maria Ramos Wellen_ _a_ - _, Eduardo Luís Canedo_ _a_ _, Camila Augusta Ventura Lima_ _b_ _,_

_Inaldo Cesar Araújo Júnior_ _b_ _, Yêda Medeiros Bastos de Almeida_ _b_ _, Marcelo Silveira Rabello_ _c_

_aPernambuco Institute of Technology, CEP 50740-540, Recife, PE, Brazil_
_bDepartment of Chemical Engineering, Federal University of Pernambuco,_

_CEP 50740-521, Recife, PE, Brazil_
_cDepartment of Materials Engineering, Federal University of Campina Grande,_

_CEP 58429-140, Campina Grande, PB, Brazil_

Received: September 20, 2013; Revised: January 16, 2015

Mechanical properties, morphology and nonisothermal crystallization of poly(3-hydroxybutyrate)
(PHB) and blends of PHB and polystyrene (PS) were studied by tensile tests, scanning electron
microscopy (SEM) and differential scanning calorimetry (DSC). A two-phase structure composed by
a PHB matrix and nearly spherical particles of PS was clearly noticed in SEM images. The presence
of small amounts (0.5% to 3%) of amorphous PS affected the crystallinity of PHB, being more evident
when high cooling rates were applied. The kinetics of nonisothermal crystallization was modeled
according to Ozawa equation. The dependence of Ozawa parameters on temperature followed the
same trend for PHB and PHB/PS blends; model parameters were found to be lower for the blends
than for the neat PHB.

Keywords: _poly(3-hydroxybutyrate) (PHB), polystyrene (PS), blends, nonisothermal crystallization_
_kinetics, Ozawa model_

1. Introduction

A current concern of the scientific community and the
society in general is the environment preservation and other
ecological issues. Committed with this cause, polymer
researchers have sought alternatives to deal with synthetic
plastic waste by directing their research to the study of
development and use of polymers obtained from renewable
sources, such as bacterial fermentation and sugar cane. Some
of these biopolymers, like poly (3-hydroxybutyrate) (PHB),
are semi crystalline, i.e., they have amorphous disordered
phase, amorphous ordered phase and crystalline phase.
Their macromolecular arrangement depends on processing
parameters and configuration of the chemical structure,
hence, the understanding of the morphology and its effects
in mechanical properties is an obvious issue 1-5 .

PHB is biodegradable and biocompatible thermoplastic
and has been used in many products, including packing and
health care industries, drugs release devices, prosthesis,
and threads for suture. A usual difficulty when dealing with
this polymer, however, is that it is rather unstable during
processing, mainly due to a short processing window
between melting and degradation temperatures. In addition
PHB is highly crystalline that, together with the high glass
transition temperature, results in a very fragile material
that limits its applications. On going research, intended on
establishing its properties, and optimizing its processing
conditions is reported in the literature 5-7 .

In previous work 8 the authors reported that the addition
of small amounts (ca., 1%) of polystyrene to PET reduced
the cold crystallization rate of PET, with no effects on
mechanical properties. This article follows the same trend
of blending polystyrene to a crystallizable polymer. In an
effort to improve the PHB properties, processability and,
in addition, to understand its crystallization behavior,
blends of PHB with small amounts of PS were produced
by melting blending and the melt crystallization parameters,
morphology and tensile properties were investigated.

2. Experimental

_2.1. Materials_

Poly (3-hydoxybutyrate) resin used in the present study,
with a weight-average molecular weight _MW_ = 340 kDa
and a melt flow rate (ASTM D-1238) 9 MFR = 26 dg/min
(2.16 kg/190 °C), was supplied by PHB Industrial SA
(Brazil). The polystyrene was a standard injection grade
material, Styron 649D, from Dow Chemical.

_2.2. Methods_

PHB/PS blends with PS content ranging between
0.5 and 3wt% were compounded in a Haake Rheomix
3000 internal mixer fitted with high-intensity (“roller” type)
rotors, for 12 min at 180°C and 60 rpm; neat PHB was also

d di i h h l

history. Immediately after mixing, the melt was quenched
in iced water to hinder PHB crystallization.

Tensile tests, according to ASTM D-638 10, were carried
out using an Emic Instrument universal testing machine with
a crosshead speed of 5 mm/min; the averages of four runs
of each formulation are reported.

Differential scanning calorimetry (DSC) analyses were
performed in a Mettler-Toledo STARe System, model
DSC1, under nitrogen flux of 50 mL/min. Samples of
approximately 6 mg were heated until fully molten at 178 °C
and kept for 5 minutes at this temperature before cooling.
Tests were run at constant rates of heating/cooling of 5, 10,
15, and 20 °C/min (Figure 1).
A JEOL, JSM-6360 scanning electron microscope was
used to study the phase morphology of PHB/PS blends,
which were cryogenically fractured in liquid nitrogen and
the fractured surface was covered with carbon for avoid the
accumulation of charges.

3. Results and Discussion

Figure 1 shows an example of a DSC scan for PHB/1%PS
blend heated/cooled at 10°C/min, including the temperature
program of the experiment. Since PS is a fully amorphous
polymer (a fact confirmed by running DSC scans of pure
PS) the melting and crystallization processes recorded by
DSC were attributed to presence of PHB in the samples. The
melting range was 148°C-178°C, which is consistent with
other results from the literature 5 . After melting, the samples
were crystallized and the crystallization peak temperatures
( _T_ c) was in the range of 80 °C-110 °C. The values of Tc
were found to be highly dependent on the cooling rate
(ϕ = | _dT_ / _dt_ |); faster rates leading the crystallization peaks
towards lower temperatures, but practically independent of
the PS content (Figure 2).

The area under the crystallization peak is related to
latent heat of crystallization, Δ _HC_, which is proportional to
crystallinity (crystalline fraction of PHB in the sample). Δ _HC_
was obtained from the area between the DSC peak output
_J_ ( _t_ ) and a suitable baseline _J_ 0( _t_ ), according to Equation (1):

where _t_ 1 and _t_ 2 are the onset and end times of the
crystallization peak, and _mS_ is the sample mass. Since
PS is an amorphous resin, the crystallinity of PHB in a
PHB/PS blend was estimated from crystallization heat as
Equation (2):

_X_ = ∆ _H_ _c_

∆
=

_c_

( 1 - _w_ PS )

1 - _w_ PS ) ∆ _H_ _m_ 0 ( _Tc_ )

(2)

_w_ PS ) ∆ _H_ _m_ 0 ( _Tc_

- _w_ PS ) ∆

_m_ _c_

_tt_ 2 [ _J_ ( _t_ ′ ) - _J_ 0 ( _t_ ′ ) ]

(1)

∫ _tt_ 12 [ _J_ ( _t_ ′ ) - _J_ 0 ( _t_ ′ )

∆ _H_ _c_ = ∫ _tt_ 12 [ _J_ ( _t_ ′ ) - _J_ 0 ( _t_ ′ ) ] _dt_ ′

∫ _t_

_H_ _c_ = ∫ _tt_ 12 [ _J_ ( _t_ ′ ) - _J_ 0 ( _t_ ′ ) ] _dt_ ′

where _w_ PS is the mass fraction of PS in the blend and ∆ _H_ _m_ 0 ( _Tc_ )
is the latent heat of fusion of 100% crystalline PHB at the
temperature of crystallization _TC_ . The later is usually known
only at the crystalline melting point _TM_ . For PHB, a value
of ∆ _H_ _m_ 0 ( _Tm_ ) = 146 J/g was used 11 .

The crystallinities of the neat PHB (XPHB) resin and
the PHB/PS (XPHB/PS) blends were found to be significantly
affected by cooling rate, as given in Figure 3 for the case of
the blends with 1% PS (remaining results are not showed
here). The general trend towards a decrease in crystallinity
with increasing cooling rates can be explained by the
decrease in the available time to develop the crystals. At
cooling rates lower than 10°C/min the crystallinity of the

Figure 2. Crystallization peak temperature of PHB and PHB/PS
blends as a function of cooling rate.

Figure 3. Decrease of PHB crystallinity upon addition of 1% PS as
a function of the cooling rate. The trend seen above was observed

_c_

_mS_

_S_

Figure 1. Typical DSC output plot for PHB/PS blend with 1% PS,

blends was equal or even higher that the crystallinity neat
PHB, which may be caused by the fact that PS particles
acted as heterogeneities and promoted the crystallinity 3,12 .
However, as the cooling rate increased, the crystallinity
of the blend decreases to values lower than those for the
neat resin. It is possible that at high cooling rates the
chains of PS do not have sufficient time to move outside of
crystallization zone, thus hindering the growth of spherulites
and contributing to lower the level of crystalinnity 13-14.

The fractional crystallization (or relative crystallinity)
during crystallization may be defined as _x_ = _X_ / _X_ ∞, where
_X_ is the crystallinity developed at time _t_ (or temperature _T_ )
and _X_ ∞ is the final crystallinity. The relative crystallinity was
estimated by integration of the DSC peak from the onset of
the crystallization:

[ _J_ ( _T_ ′ ) - _J_ 0 ( _T_ ′ ) ]

= ∫ _TT_ 1 [ _J_ ( _T_ ′ ) - _J_ 0 ( _T_ ′ ) ] _dT_ ′

_x_ = ∫ _TTT_ 1 [ _J_ ( _T_ ′ ) - _J_ 0 ( _T_ ′ ) ] _dT_

∫ _T_

∫ _TT_ 1

∫ _TT_ 1 2

of either time ( _t_ ) or temperature ( _T_ ), since the temperature
is a linear function of time at constant heat rate, _T_ = _T_ 0 − ϕt,
where ϕ is the cooling rate and _T_ 0 is the temperature at the
starting point of the cooling run.

Figure 4 shows the fractional crystallization for several
cooling rates as a function of temperature, for a PHB/PS
blend with 1% PS. In these results a deviation from linearity
at the end of crystallization process is observed, which
increases with increasing cooling rates. This deviation
may be associated with development of thermally unstable
crystalline entities and/or crystallization occurring at the
impingement zones, and generally originating imperfect
crystals of lower crystallinity degree, a phenomenon called
secondary crystallization 15-17. The results agree with the
discussion of Figure 3.

Ozawa model 18 was used to better evaluate the kinetics
of crystallization. The model assumes that nonisothermal
crystallization is governed by the same mechanism proposed
by Avrami 19 for isothermal crystallization. An interesting
feature of Ozawa model is the possibility to compare the
results of crystallization during continuous cooling/heating
with those obtained by means of the Avrami equation under
isothermal conditions. Ozawa model requires a constant rate
of temperature change, ϕ = | _dT_ / _dt|_, and has been successfully
used to study a number of nonisothermal crystallization
processes 13,15 . Ozawa kinetic model is given by:

_x_ = 1 - exp (−φ _k_ − _m_ ) (4)

where _x_ is the fractional crystallization, ϕ is the cooling rate,
and κ and _m_ are the Ozawa parameters, which are function
of the temperature and depend on nucleation and growth
mechanisms. From Equation (4) we obtain:

ln [− ln(1  - _x_ ) ] = ln κ  - _m_ ln (φ) (5)

_T_ 2

[ _J_ ( _T_ ′ ) - _J_ 0 ( _T_ ′ ) ]

_J_ ( _T_ ′ ) - _J_ 0 ( _T_ ′ ) ] _dT_

( _T_ ′ ) - _J_ 0 ( _T_ ′ )

′ ) - _J_ 0 ( _T_ ′ ) ] _dT_ ′

(3)

where _J_ ( _T_ ) is the DSC output in terms of temperature, _J_ 0( _T_ )
is the virtual baseline signal during the event, _T_ 1 and _T_ 2 are
the onset and end temperatures of the crystallization peak,
and _T_ is an intermediate temperature, _T_ 1 ≤ _T_ ≤ _T_ 2. The
fractional crystallization may be considered as a function

Consequently, Ozawa model predicts a linear relationship
between ln[−ln(1− _x_ )] and lnϕ at constant temperature.
Ozawa parameters for the crystallization of PHB and
PHB/PS blends with 1% and 3% PS were determined at
several temperatures between 80 °C and 110 °C (Table 1).

Figure 5 shows graphically the dependence of the
Ozawa parameters with temperature for neat PHB and a
blend with 3% PS. The trend for the two types of samples
is similar, but the values for the blends are significantly
Figure 4. Typical crystallization plot (fractional crystallization _vs_ lower than for the neat polymer. The parameter κ also
temperature) for PHB/PS blend with 1% PS. showed much lower values for the blends and, again, a

Table 1. Kinetic parameters (Ozawa model) for PHB and PHB/PS blends at different temperatures ln κ.

110 °C 105 °C 100 °C 95 °C 90 °C 80 °C

PHB - 5.257 5.700 5.709 5.464 PHB + 1%PS 1.881 - 4.865 - 5.132 4.888
PHB + 3%PS 3.707 - 5.091 - 4.748 4.528

_m_

110 °C 105 °C 100 °C 95 °C 90 °C 80 °C

PHB - 3.23 2.98 2.67 2.35 PHB + 1%PS 2.04 - 2.43 - 2.06 1.67
PHB + 3%PS 3 19 2 71 1 97 1 49

Figure 5. Ozawa parameters, Equation (4), for PHB and a PHB/PS blend with 3% PS.

Table 2. Mechanical properties of PHB and PHB/PS blends.

PHB PHB + 0.5% PS PHB + 3.0% PS

Elastic modulus (MPa) 826.3 ± 24.2 781.4 ± 33.6 765.3 ± 32.7
Tensile strength (MPa) 33.1 ± 0.2 34.4 ± 0.9 33.2 ± 0.5
Elongation at break (%) 5.7 ± 0.2 6.5 ± 0.4 5.8 ± 0.1

Figure 6. SEM images of neat PHB (a) and blend with 3% PS (b).

similar trend with temperature is observed. The lower
Ozawa rate parameter κ obtained with the blends is related
to the presence of PS chains, which act as irregularities at
the crystallization border of PHB and, therefore, hinder the
crystallization. This is consistent with results previously
discussed (Figure 3). The Ozawa exponent _m_ is related to
the size and perfection of crystallites; high values of _m_ can
be associated to large and stable, more perfect crystallites,
whereas lower values of _m_ denote smaller and/or less stable
crystals 20-22.

Table 2 presents the results of mechanical properties
f d h bl d i h S h l i

similar, showing that the presence of small amounts of
PS did not cause significant variations in the mechanical
properties of PHB, except for the elastic modulus that had
a reduction of 8% for the blend with 3% PS. Since the
degree of crystallinity of PHB did not change much with
the presence of PS (Figure 3), the mechanical properties
follow the same trend.

The morphology of PHB and its blend with PS were
examined by SEM and typical images are shown in Figure 6.
A two-phase structure composed by a PHB matrix and nearly
spherical particles of PS is clearly noticed. Some PS particles

i d h d h i h f d f

which may indicate reasonable interfacial interactions
between the components.

4. Conclusions

Nonisothermal melt crystallization kinetics of PHB
and PHB/PS blends with small amounts (0.5% to 3% wt)
of amorphous PS was investigated by differential scanning
calorimetry (DSC), and the kinetics parameters were
determined using the Ozawa model. In all situation cooling
rates influenced the mechanisms of PHB crystallization,
where higher rates contributed to less stable crystallization
process. PHB/PS blends presented two-phase structure
composed by a PHB matrix and spherical particles of PS

References

1. Renstad R, Karlsson S, Albertsson A, Werner P and Westdahl M.
Influence of Processing Parameters on the Mass Crystallinity
of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate). _Polymer_
_International_ [. 1997; 43(3):201-209. http://dx.doi.org/10.1002/](http://dx.doi.org/10.1002/%0x28SICI%0x291097-0126%0x28199707%0x2943:3%3c201::AID-PI761%3e3.0.CO;2-7)
[(SICI)1097-0126(199707)43:3<201::AID-PI761>3.0.CO;2-7.](http://dx.doi.org/10.1002/%0x28SICI%0x291097-0126%0x28199707%0x2943:3%3c201::AID-PI761%3e3.0.CO;2-7)

2. Reddy CS, Ghai R, Rashmi and Kalia VC.
Polyhydroxyalkanoates: an overview. _Bioresource Technology_ .
[2003; 87(2):137-146. http://dx.doi.org/10.1016/S0960-](http://dx.doi.org/10.1016/S0960-8524%0x2802%0x2900212-2)
[8524(02)00212-2. PMid:12765352](http://dx.doi.org/10.1016/S0960-8524%0x2802%0x2900212-2)

3. Cimmino S, Iodice P, Martuscelli E and Silvestre C. Poly(3-D(-)
hydroxybutyrate)/atactic poly(methylmethacrylate) blends:
Morphology, miscibility and crystallization relationships.
_ThermochimicaActa_ [. 1998;321(1-2):89-98. http://dx.doi.](http://dx.doi.org/10.1016/S0040-6031%0x2898%0x2900444-4)
[org/10.1016/S0040-6031(98)00444-4.](http://dx.doi.org/10.1016/S0040-6031%0x2898%0x2900444-4)

4. El-Hadi A, Schnabel R, Straube E, Müller G and Henning
S. Correlation between degree of crystallinity, morphology,
glass temperature, mechanical properties and biodegradation
of poly (3-hydroxyalkanoate) PHAs and their blends. _Polymer_
_Testing_ [. 2002; 21(6):665-674. http://dx.doi.org/10.1016/S0142-](http://dx.doi.org/10.1016/S0142-9418%0x2801%0x2900142-8)
[9418(01)00142-8.](http://dx.doi.org/10.1016/S0142-9418%0x2801%0x2900142-8)

5. Wellen RMR, Rabello MS, Fechine GJM and Canedo EL.
The melting behaviour of poly(3-hydroxybutyrate) by DSC.
Reproducibility study. _Polymer Testing_ . 2013; 32(2):215-220.
[http://dx.doi.org/10.1016/j.polymertesting.2012.11.001.](http://dx.doi.org/10.1016/j.polymertesting.2012.11.001)

6. Avella M, Martuscelli E and Greco P. Crystallization behaviour
of poly(ethylene oxide) from poly(3-hydroxybutyrate)/
poly(ethylene oxide) blends: phase structuring, morphology
and thermal behaviour. _Polymer_ [. 1991; 32(9):1647-1653. http://](http://dx.doi.org/10.1016/0032-3861%0x2891%0x2990401-4)
[dx.doi.org/10.1016/0032-3861(91)90401-4.](http://dx.doi.org/10.1016/0032-3861%0x2891%0x2990401-4)

7. An Y, Dong L, Xing P, Zhuang Y, Mo Z and Feng Z.
Crystallization kinetics and morphology of poly(βhydroxybutyrate) and poly(vinyl acetate) blends. _European_
_Polymer Journal_ [. 1997; 33(9):1449-1452. http://dx.doi.](http://dx.doi.org/10.1016/S0014-3057%0x2897%0x2900015-3)
[org/10.1016/S0014-3057(97)00015-3.](http://dx.doi.org/10.1016/S0014-3057%0x2897%0x2900015-3)

8. Wellen RMR and Rabello MS. Redução da velocidade
de cristalização a frio do PET napresença de poliestireno.
_Polímeros: Ciências e Tecnologia_ . 2007; 17(2):113-122.

9. American Society for Testing and Materials - ASTM. _ASTM_
_D638-03: standard test method for tensile properties of plastics_ .
West Conshohocken; 2003.

10. American Society for Testing and Materials - ASTM. _ASTM_
_D1238-04: standard test method for melt flow rates of_
_thermoplastics by extrusion plastometer_ . West Conshohocken;
2004.

11. Barham PJ, Keller A, Otun EL and Holmes PA. Crystallization

which were observed by SEM images. The mechanical
behaviour was also investigated and the results showed
that the presence of PS had little influence in PHB tensile
properties.

Acknowledgements

The authors wish to thanks Prof. Agnelli (UFSCar, São
Carlos, SP, Brazil) for compounding de PHB/PS blends,
PHB Industrial SA (Brazil) for the PHB, Mettler-Toledo
(Brazil) for the DSC scans. The authors also thank _Conselho_
_Nacional de DesenvolvimentoCientífico e Tecnológico_
(CNPq/Brazil) and _Fundação de Amparo à Ciência e_
_Tecnologia do Estado de Pernambuco_ (FACEPE/Brazil)
for financial support.

hydroxybutyrate. _Journal of Materials Science_ . 1984;
[19(9):2781-2794. http://dx.doi.org/10.1007/BF01026954.](http://dx.doi.org/10.1007/BF01026954)

12. Liu J, Yang L, Wang Z, Dong S and Liu J. Effect of nucleating
agents on the crystallization of poly(3-hydroxybutyrate-co-3hydroxyvalerate). _Journal of Applied Polymer Science_ . 2002;
[86(9):2145-2152. http://dx.doi.org/10.1002/app.11023.](http://dx.doi.org/10.1002/app.11023)

13. Ziaee Z and Supaphol P. Non-isothermal melt- and coldcrystallization kinetics of poly(3-hydroxybutyrate). _Polymer_
_Testing_ [. 2006; 25(6):807-818. http://dx.doi.org/10.1016/j.](http://dx.doi.org/10.1016/j.polymertesting.2006.04.009)
[polymertesting.2006.04.009.](http://dx.doi.org/10.1016/j.polymertesting.2006.04.009)

14. Chen C, Fei B, Peng S, Zhuang Y, Dong L and Feng Z.
Nonisothermal crystallization and melting behavior of poly(3hydroxybutyrate) and maleated poly(3-hydroxybutyrate).
_European Polymer Journal_ [. 2002; 38(8):1663-1670. http://](http://dx.doi.org/10.1016/S0014-3057%0x2802%0x2900046-0)
[dx.doi.org/10.1016/S0014-3057(02)00046-0.](http://dx.doi.org/10.1016/S0014-3057%0x2802%0x2900046-0)

15. Hwang H, Jung C and Lee W. Crystallinity and thermal
characterization of P(HB-HV)/PVAc blend. _European Polymer_
_Journal_ [. 1998; 34(7):949-953. http://dx.doi.org/10.1016/](http://dx.doi.org/10.1016/S0014-3057%0x2897%0x2900215-2)
[S0014-3057(97)00215-2.](http://dx.doi.org/10.1016/S0014-3057%0x2897%0x2900215-2)

16. Kong X, Yang X, Li G, Zhao X, Zhou E and Ma D.
Nonisothermal crystallization kinetics: poly(ethylene
terephthalate)–poly(ethylene oxide) segmented copolymer
and poly(ethylene oxide) homopolymer. _European Polymer_
_Journal_ [. 2001; 37(9):1855-1862. http://dx.doi.org/10.1016/](http://dx.doi.org/10.1016/S0014-3057%0x2801%0x2900046-5)
[S0014-3057(01)00046-5.](http://dx.doi.org/10.1016/S0014-3057%0x2801%0x2900046-5)

17. Chen C, Fei B, Peng S, ZhuangY, DongL and FengZ.
Nonisothermal crystallization and melting behavior of poly(3hydroxybutyrate) and maleated poly(3-hydroxybutyrate).
_European Polymer Journal_ [. 2002; 38(8):1663-1670. http://](http://dx.doi.org/10.1016/S0014-3057%0x2802%0x2900046-0)
[dx.doi.org/10.1016/S0014-3057(02)00046-0.](http://dx.doi.org/10.1016/S0014-3057%0x2802%0x2900046-0)

18. Ozawa T. Kinetics of non-isothermal crystallization. _Polymer_ .
[1971; 12(3):150-158. http://dx.doi.org/10.1016/0032-](http://dx.doi.org/10.1016/0032-3861%0x2871%0x2990041-3)
[3861(71)90041-3.](http://dx.doi.org/10.1016/0032-3861%0x2871%0x2990041-3)

19. Avrami M. Kinetics of phase change. I General theory. _The_
_Journal of Chemical Physics_ [. 1939; 7(12):1103-1112. http://](http://dx.doi.org/10.1063/1.1750380)
[dx.doi.org/10.1063/1.1750380.](http://dx.doi.org/10.1063/1.1750380)

20. Run M, Yao C and Wang Y. Morphology, isothermal and
non-isothermal crystallization kinetics of poly(methylene
terephthalate). _European Polymer Journal_ . 2006; 42(3):655[662. http://dx.doi.org/10.1016/j.eurpolymj.2005.08.010.](http://dx.doi.org/10.1016/j.eurpolymj.2005.08.010)

21. Liu T, Mo Z and Zhang H. Nonisothermal crystallization
behavior of a novel poly(aryl ether ketone): PEDEKmK. _Journal_
_of Applied Polymer Science_ [. 1998; 67(5):815-821. http://dx.doi.](http://dx.doi.org/10.1002/%0x28SICI%0x291097-4628%0x2819980131%0x2967:5%3c815::AID-APP6%3e3.0.CO;2-W)
[org/10.1002/(SICI)1097-4628(19980131)67:5<815::AID-](http://dx.doi.org/10.1002/%0x28SICI%0x291097-4628%0x2819980131%0x2967:5%3c815::AID-APP6%3e3.0.CO;2-W)
[APP6>3.0.CO;2-W.](http://dx.doi.org/10.1002/%0x28SICI%0x291097-4628%0x2819980131%0x2967:5%3c815::AID-APP6%3e3.0.CO;2-W)

22. Van Krevelen DW. _Properties of polymers_ . 3rd ed. Amsterdam:

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