Thermal and crystallization behavior of engineering polyblends. I. Glass reinforced polyphenylene sulfide with polyethylene terephthalate

The thermal and crystallization behavior of blends of glass fiber reinforced polyphenylene sulfide (PPS) with polyethylene terephthalate (PET) has been reported. The blends showed two overlapping melting peaks and two separate crystallization peaks. The heat of crystallization of PPS was found to decrease continuously with increasing PET content, whereas the heat of crystallization of PET was found to increase with increasing PPS content. This indicates that the degree of crystallinity of PPS is reduced whereas that of PET is increased as a result of blending. It is interesting to note that the combined heats of fusion of the blends were marginally higher than those calculated by proportional additivity rule in spite of the drop in the heat of crystallization of PPS. The temperature onset of crystallization of PET in the blends shifted to higher temperature whereas there was no significant change in the crystallization temperature of PPS. The increase in the temperature of crystallization of PET indicates enhanced nucleation. The isothermal crystallization studies of the component polymers revealed that both the component polymers crystallized at a relatively faster rate in the blend. The crystallization rate of PPS was found to increase significantly with increasing PET content. A significant increase in the rate of crystallization of PET was also observed in the blends. The acceleration of crystallization rate of PET in the blends was more pronounced as compared to that of PPS. The acceleration in the PET crystallization rate was attributed to the presence of glass fibers and crystallized PPS.     

Nonisothermal crystallization of poly(phenylene sulfide) in presence of molten state of crystalline polyamide 6

The nonisothermal crystallization and melting behavior of a poly(phenylene sulfide) (PPS) blend with polyamide 6 (PA6) were investigated by differential scanning calorimetry. The results indicate that the crystallization parameters for PPS become modified to a greater extent than those for PA6 in the blends. The PPS and PA6 crystallize at high temperature as a result of blending. The crystallization temperatures of PPS in its blends are always higher than that of pure PPS and are independent of the melting temperature and the residence time at that temperature. The PPS crystallization peak becomes narrower and the crystallization temperature shifts to a higher temperature, suggesting a faster rate of crystallization as a result of blending with PA6. This enhancement in the nucleation of PPS could be attributed to the possible presence of interfacial interactions between the component polymers to induce heterogeneous nucleation. On the other hand, the increase in the crystallization temperature of PA6 can be attributed to the heterogeneous nucleation provided by the already crystallized PPS. The heterogeneous nucleation induced by interfacial interactions depends on the temperature at which the polymers remain in the molten state and on the storage time at this temperature. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 3033–3039, 1999     

Multiple melting behavior of polyphenylene sulfide blends with polyamide 6

Although there are many studies on the multiple melting behavior of polyphenylene sulfide (PPS) homopolymer, similar investigations on PPS component in PPS blends with thermoplastics are relatively rare. In the present paper, the multiple melting behavior of PPS blends with polyamide 6 (PA6) have been investigated by differential scanning calorimetry (DSC). The double melting peaks are also observed for PPS in the blends. Although the annealing temperature and time as well as the heating rate of DSC scanning are different, the lower melting peak temperature of PPS in the blend is higher than that of pure PPS and the higher melting peak temperature is lower than that of pure PPS. It is suggested that PA6 can accelerate the cold‐crystallization of amorphous PPS due to the possible presence of interfacial interaction between the component polymers to induce the heterogeneous nucleation, and increase the perfection of PPS crystals. The multiple melting behavior of PPS in the blends are explained by recrystallization. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1579–1585, 2000     

PPS/TLCP共混体系非等温结晶行为及性能研究

研究了聚苯硫醚（PPS）与全芳及半芳族热致性液晶（TLCP）共混物的结晶和熔融行为;通过差示扫描量热仪（DSC）和偏光显微镜（PLM）分析了PPS的结晶过程和晶体微观结构,并研究了材料力学性能。研究表明,加入少量全芳或半芳族TLCP,可显著提高PPS最大结晶温度和结晶速率,全芳族TLCP起异向成核作用,而半芳族TLCP促进晶体增长;加入质量分数为2％的全芳族TLCP,可同时提高PPS的拉伸和冲击强度。     

Poly(p-phenylene sulfide)/liquid crystalline polymer blends. II. Crystallization kinetics

The crystallization kinetics of blends made of poly(p-phenylene sulfide) (PPS) with a liquid crystalline polymer (LCP) was studied. The blends were found to be immiscible by dynamic mechanical thermal analysis (DMTA). Results of non-isothermal and isothermal crystallization experiments made by differential scanning calorimetry (DSC) showed that both components had their crystallization temperatures increased; also the LCP melting temperature was found to increase in the blends. It was concluded that the addition of LCP to the PPS increased the PPS overall crystallization rate due to heterogeneous nucleation. The fold interfacial free energy, σ_e of the PPS in the blends was observed not to vary with composition. © 1996 John Wiley & Sons, Inc.     

Double melting phenomena of polyphenylene sulfide and its blends

The melting behavior of PPS (polyphenylene sulfide) and its blends with PSF (bisphenol A polysulfone) and PEK-C (polyetherketone with phthalidylidene groups) are investigated with DSC technique. It is found that, with a rise in melt temperature T_melt and melt time t_melt, the intensities of the lower melting peaks of PPS increase while those of the upper ones decrease or disappear in some cases, which can be attributed to the obstructive effect of branching or crosslinking of PPS macromolecules on the crystallization of PPS at higher temperature. As the annealing crystallization temperature increases, both the peak temperatures and intensities of the lower melting peaks of PPS increase. PSF and PEK-C have no influence on the lower melting peaks of PPS but are unfavorable to the crystallization of the higher melting species. The double melting behavior of the PPS component in the blends is much more susceptible to the changes in T_melt and t_melt than that of neat PPS. © 1994 John Wiley & Sons, Inc.     

Effect of PMR‐POI on the melt behavior and isothermal crystallization of poly(phenylene sulfide)

The crystallization behavior of neat PPS and PPS in blends with PMR‐POI prepared by melt mixing were investigated by differential scanning calorimetry (DSC). It was found that POI was an effective nucleation agent of the crystallization for PPS. The enthalpy of crystallization of PPS in the blends increased compared with that of neat PPS. During isothermal crystallization from melt, the dependence of relative degree of crystallinity on time was described by the Avrami equation. It has been shown that the addition of POI causes an increase in the overall crystallization rate of PPS; it also changed the mechanism of nucleation of the PHB crystals from homogeneous nucleation to heterogeneous nucleation. The equilibrium melting temperature of PPS and PPS/POI blends were determined. The analysis of kinetic data according to nucleation theories shows that the increase in crystallization rate of PPS in the composite is due to the decrease in surface energy of the extremity surface. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 436–442, 2002     

Effect of high-performance polymers on crystallization and multiple melting behavior of poly(phenylene sulfide)

The crystallization and multiple melting behavior of poly(phenylene sulfide) (PPS) and its blends with amorphous thermoplastic bisphenol A polysulfone (PSF) and phenolphthalein poly(ether ketone) (PEK-C), crystalline thermoplastic poly(ether ether ketone) (PEEK), and thermosetting bismaleimide (BMI) resin were investigated by a differential scanning calorimeter (DSC). The addition of PSF and PEK-C was found to have no influence on the crystallization temperature (T_c) and heat of crystallization (ΔH_c) of PPS. A significant increase in the value of T_c and the intensity of the T_c peak of PPS was observed and the crystallization of PPS can be accelerated in the presence of the PEEK component. An increase in the T_c of PPS can also be accelerated in the BMI/PPS blend, but was no more significant than that in the PEEK/PPS blend. The T_c of PPS in the PEEK/PPS blends is dependent on the maximum temperature of the heating scans and can be divided into three temperature regions. The addition of a second component has no influence on the formation of a multiple melting peak. The double melting peaks can also be observed when PPS and its blends are crystallized dynamically from the molten state. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 637–644, 1998     

Investigation on the crystallization behavior of poly(ether ether ketone)/poly(phenylene sulfide) blends

The morphology of nonisothermally crystallized poly(phenylene sulfide) (PPS) and its blend with poly (ether ether ketone) (PEEK) have been observed by polarized optical microscope (POM) equipped with a hot stage. The nonisothermal crystallization behavior of PPS and PEEK/PPS blend has also been investigated by differential scanning calorimetry (DSC). The maximum crystallization temperature for PEEK/PPS blend is about 15°C higher than that of neat PPS, and the crystallization rate, characterized by half crystallization time, of the PEEK/PPS blend is also higher than that of the neat PPS. These results indicate that the PEEK acts as an effective nucleation agent and greatly accelerates the crystallization rate of PPS. The Ozawa model was used to analyze the nonisothermal crystallization kinetics of PPS and its blends. The Avrami exponent values of neat PPS are higher than that of its blend, which shows that the presence of PEEK changed the nucleation type of PPS from homogeneous nucleation to heterogeneous nucleation. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Non-Isothermal Crystallization of High-Impact Polystyrene/Poly(Phenylene Sulfide) Blends

The morphology of isothermally crystallized poly(phenylene sulfide) (PPS) and a blend combining it with high-impact polystyrene (HIPS) were observed through a polarized optical microscope equipped with a CSS450 hot-stage. The crystalline superstructure of PPS is mainly spherulite, and it was found that the presence of HIPS has little influence on the morphology of PPS, but decreases the nucleation rate of PPS. The effect of HIPS on the non-isothermal crystallization of PPS was investigated by differential scanning calorimetry (DSC). The maximum and onset crystallization temperatures for the HIPS/PPS blend were about 10°C lower than those of neat PPS, which indicates that the crystallization of PPS was retarded by HIPS. The Ozawa model was used to analyze the non-isothermal crystallization kinetics of PPS and its blends. The Avrami exponent values of neat PPS were higher than those of its blend, which shows that the presence of HIPS changed both the nucleation rate and the crystallization rate of PPS.     

Thermal and crystallization behavior of alloys of polyphenylene sulfide and high-density polyethylene

The thermal and crystallization behavior of alloys of two semicrystalline thermoplastics, namely, polyphenylene sulfide (PPS) and high-density polyethylene (HDPE) were studied by differential scanning calorimetry (DSC). The presence of a second component in the alloy was found to influence the nonisothermal crystallization process of both the component polymers. The crystallization temperature of PPS in the DSC cooling scan is significantly affected, whereas there is little variation in case of HDPE in the composition range studied. The morphological changes observed in both PPS and HDPE are similar. These include larger crystallite size, a narrower crystallite size distribution, and a lower degree of crystallinity in the alloys as compared to the homopolymers. The isothermal crystallization of the component polymers in the alloys is significantly different from that of the homopolymer. The composition dependence of the overall rate of isothermal crystallization is explained in terms of the competing processes of nucleation and crystal growth. The results show that blending of a high melting polymer with a low melting polymer accelerates the crystallization of the high melting polymer, even at low levels of about 10% of the lower melting component.     

Crystallization kinetics and nucleating agents for enhancing the crystallization of poly(p-phenylene sulfide)

An experimental study of crystallization kinetics and the influence of nucleating agents on the solidification of poly(p-phenylene sulfide) (PPS) is described. The effect of molecular weight is considered by investigating PPS samples having different viscosity levels. We studied the effect of a range of nucleating agents including aluminum oxide, calcium oxide, silicon dioxide, titanium dioxide, kaolin, and talc. All of these compounds were found to enhance the rate of crystallization; in particular, silicon dioxide, kaolin, and talc were the most effective nucleating agents. An effort to study particle size effects of the silicon dioxide showed that the nucleation was very sensitive to the source of the material. These studies did, however, show that nucleation rates tended to increase with decreasing particle size and increasing loading of silicon dioxide. Comparison of PPS crystallization rates with those of other polymers indicates that it crystallizes much more slowly than polyethylene or isotactic polypropylene and is slower than polyetherether-ketone, when comparisons are made on an equivalent basis. PPS crystallizes at similar rates to polyethylene terephthalate (PET). However, our nucleated PPS does not crystallize as rapidly as nucleated PET.     

PPS／PEEK熔融共混物DSC多次扫描研究

借助ＤＳＣ研究ＰＰＳ／ＰＥＥＫ共混物熔融时间，ＰＥＥＫ粒径及ＰＰＳ组分对共混物中ＰＥＥＫ结晶熔融行为的影响，结果表明，ＰＥＥＫ粒径由５００～１０００μｍ减小至２００～５００μｍ时，ＰＥＥＫ与ＰＰＳ相互作用增大，ＰＥＥＫ的结晶峰由单峰分裂为双峰，其高温结晶峰向高温移动，峰强随熔融时间延长而减弱，低温结晶峰向低温移动，峰强随熔融时间延长而增大，熔融时间延长时，退火后ＰＥＥＫ的低温熔融峰强增大，而高温熔     

PET离聚物共混体系的结晶与熔融行为研究

利用ＤＳＣ对聚对苯二甲酸乙二酯（ＰＥＴ）与离聚物Ｓｕｒｌｙｎ和Ａｃｌｙｎ系列组成的共混体系的结晶与熔融行为进行了研究．结果表明，离聚物对ＰＥＴ的低温与高温结晶都有十分明显的促进作用，离聚物Ｎａ盐比离聚物Ｚｎ盐对ＰＥＴ的结晶加速作用显著。共混体系的熔融热焓随离聚物Ｎａ盐含量的增加有所降低，随Ｚｎ盐含量的增加稍有提高，两者的熔点及熔限与熔融热焓的变化规律一致．     

Crystallization and melting behavior of partially miscible six‐armed poly(l‐lactic acid)/poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) blends

The crystallization kinetics and spherulitic morphology of six‐armed poly(L‐lactic acid) (6a‐PLLA)/poly(3‐hydroxybutyrate‐co?3‐hydroxyvalerate) (PHBV) crystalline/crystalline partially miscible blends were investigated with differential scanning calorimetry and polarized optical microscopy in this study. Avrami analysis was used to describe the isothermal crystallization process of the neat polymers and their blends. The results suggest that blending had a complex influence on the crystallization rate of the two components during the isothermal crystallization process. Also, the crystallization mechanism of these blends was different from that of the neat polymers. The melting behavior of these blends was also studied after crystallization at various crystallization temperatures. The crystallization of PHBV at 125°C was difficult, so no melting peaks were found. However, it was interesting to find a weak melting peak, which arose from the PHBV component for the 20/80 6a‐PLLA/PHBV blend after crystallization at 125°C, and it is discussed in detail. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42548.     

Study on Thermal Properties and Crystallization Behavior of Blends of Poly(phenylene sulfide)/Poly(ether imide)

The thermal behavior of poly(phenylene sulfide) (PPS) blends with poly(ether imide) (PEI) was studied by differential scanning calorimeter (DSC). The crystallization temperature of PPS in blends shifted from 216.8°C to 226.4°C upon addition of 20–70% PEI contents. The heat of crystallization remained unchanged with less than 50% PEI in blends, whereas the heat of fusion decreased with increasing PEI content. The isothermal crystallization indicated that incorporating PEI would accelerate the crystallization rate of PPS. The activation energy of crystallization increased with addition of PEI. The equilibrium melting point of PPS/PEI blends was not changed with compositions.     

Thermal studies of blends of poly(phenylene sulfide) (PPS) with poly(phenylene sulfide sulfone) (PPSS) and with poly(phenylene sulfide ether) (PPSE)

The miscibilities of poly(phenylene) sulfide/poly(phenylene sulfide sulfone) (PPS/PPSS) and poly(phenylene) sulfide/poly(phenylene sulfide ether) (PPS/PPSE) blends were invesigated in terms of shifts of glass transition temperatures T_g of pure PPS, PPSS, a dn PPSE. The crystallization kinetics of PPS/PPSS blends was also studied as a function of molar composition. The PPS/PPSS and PPS/PPSE blends are respectively partially and fully miscible. PPSE shows a plasticizing effect on PPS as does PPS on PPSS, which necessarily improves te processibility in the respective systems. We can control T_g and melting temperature T_m of PPS by varying amounts of PPSE in blends. The melt crystallization temperature T_mc of PPS/PPSE blends was higher than that of the PPSE homopolymer. Therefore, these blends require shorter cycle times in processing than pure PPSE. The overall rate of crystallization for PPS/PPSS blends follows the Avrami equation with an exponent ?2. The maximal rate of crystallization for PPS/PPSS blends occurs at a temperatre higher by 10°C than that for PPS, while the crystallization half time t_1/2 is 4 times shorter. In the cold crystallization range, crystal growth rates increase and Avrami exponents decrease significantly as the temperature increases.     

PET/PP共混体系的熔融及非等温结晶行为

用熔融共混法制备了聚对苯二甲酸乙二醇酯(PET)/聚丙烯(PP)复合材料。对复合体系的形态结构、熔融及非等温结晶行为进行了研究。结果表明:两相界面或PP相对PET结晶无明显的异相成核效应;当PP为连续相时,已结晶的极性PET粒子对PP的异相成核作用较为明显;而当PP为分散相时,固态的PET在一定程度上阻碍了PP分子链的运动,促使PP结晶均相成核趋势增加。与纯PET或PP相比,共混体系中两组分结晶的完善程度都有所下降。     

Polymer compatibility: Ternary blends of poly(vinylidene chloride-co-vinyl chloride), poly(vinyl chloride) and poly(acrylonitrile-co-butadiene)

Mixtures of two compatible polymers, poly(vinyl chloride) and poly(acrylonitrile-co-butadiene) containing 40 percent acrylonitrile, can be compatible with poly(vinylidene chloride-co-vinyl chloride), which is incompatible and partially compatible respectively with these two polymers. The crystalline melting temperature and relative heat of fusion of poly(vinylidene chloride-co-vinyl chloride) in blends are higher than those in the pure component. This is attributed to greater ordering of the polymer chains in the crystalline phases of the blends. Replacing the rubber by poly(acrylonitrile-cobutadiene) containing 30 percent acrylonitrile, shows that these three polymers, in which each pair is incompatible or at most partially compatible, also form compatible ternary blends. The crystalline melting temperature is higher and relative heat of fusion lower than those in the pure component. This is attributed to dissolving of parts of the polymer chains originally located in the crystalline phases in the amorphous phases of the blends.     

Crystallization of poly(tetramethylene succinate) in blends with poly(ϵ‐caprolactone) and poly(ethylene terephthalate)

The crystallization behavior of polymer blends of poly(tetramethylene succinate) (PTMS) with poly(?‐caprolactone) (PCL) or poly(ethylene terephthalate) (PET) was investigated with differential scanning calorimetry under isothermal and nonisothermal conditions. The blends were prepared by solution casting and precipitation, respectively. The constituent polymers were semicrystalline materials and crystallized nearly independently in the blends. The addition of the second component to PTMS showed that PCL did not significantly influence the crystallinity of the constituents in the blends under isothermal conditions, whereas the crystallization of PTMS was slightly suppressed by crystalline PET. Nonisothermal crystallization under constant cooling rates was examined in terms of a quasi‐isothermal Avrami approach. In blends, the rates of crystallization were differently influenced by the second component. The rate of the constituent that crystallized at the higher temperature was barely influenced by the second component being in the molten state, whereas the rate of the second component, crystallizing when the first component was already crystalline, was altered differently under isothermal and nonisothermal conditions. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 149–160, 2004