Thermo-stability of Conductive Blends of Polyaniline/Poly(styrene-co-maleic anhydride)

Di-2-ethylhexylsulfosuccinate sodium salt(AOT)doped conducting polyaniline(PANI-AOT)was chemically polymerized.It was dissolved into a weakly polar solvent(toluene)and secondary doped with m-cresl.The conductivity of PANI-AOT was sharply increased form 30S/cm to 400S/cm after the secondary doping.Then the conducting polymer was firstly blended with a typical thermoplastic polymer,poly(styrene-co-maleic anhydride)(SMA)by soluon blending method.The conductivity of PANI-AOT/SMA was relatively maintained even at 200℃for several minutes.The TGA analysis also indicated that the thermostabilities of the blends were obviously improved compared with those of PANI-AOT.     

PET／PA66／液晶共聚酯酰胺共混体系的流变性能

采用ＳＥＭ１、热偏光显微研究了聚对苯二甲乙二酯（ＰＥＴ）／聚酰胺６６（ＰＡ６６）／热致液晶共聚酯酰胺（ＬＣ３０）三元共混物的形态结构;利用Ｉｎｓｔｒｏｎ３２１１型毛细管流变仪研究了共混物的流变性能,结果表明：ＰＥＴ／ＰＡ６６／ＬＣ３０共混物为一热力学不相容的多相聚合物体系,ＬＣ３０的加入提高了ＰＥＴ／ＰＡ６６的相容性,有效地改善了ＰＥＴ／ＰＡ６６共混物的流变性能,ＰＥＴ／ＰＡ６６／ＬＣ３０三元共混     

聚乙烯在天然橡胶／聚乙烯共混体系中的结晶行为

本工作主要利用DSC、x-射线衍射、小角激光光散射以及偏光显微镜等方法,对天然橡胶/低密度聚乙烯共混体系(NR/LDPE)中LDPE的晶体结构、结晶度、球晶尺寸和形态、微晶尺寸、成核过程以及结晶动力学等方面进行了研究,得到了一些有意义的结果。     

Poly(hydroxybutyrate) and epichlorohydrin elastomers blends: Phase behavior and morphology

This work studied blends of PHB with epichlorohydrin elastomers, the PEP homopolymer and its copolymer with ethylene oxide, ECO. PHB is a microbial polyester, which is accumulated intracellularly by a large number of microorganisms, presenting characteristics of biodegradability and biocompatibility. It presents a high degree of crystallinity, so is a quite brittle material, and may undergo degradation when is kept for a relatively short time at a temperature above its melting point, about 180 °C. PEP and ECO are linear and amorphous elastomers, exhibit miscibility with many aliphatic polyesters and these elastomers have been used in various branches of technology, such as the automotive industry. The proposed systems combine a polymer with high crystallinity and biodegradability, PHB, with amorphous epichlorohydrin elastomers. Blends were prepared by casting from chloroform solution at different compositions (0, 20, 40, 50, 60, 80 and 100 wt% of PHB). The phase behavior of PHB/PEP and PHB/ECO blends were studied by differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and the morphology of the crystalline phase of PHB had been examined by optical microscopy. Blends of PHB/PEP and PHB/ECO have been described in literature as miscible. However, our results from the DSC and DMA show that PHB/PEP and PHB/ECO blends are immiscible. This behavior should be related to the molecular weight of polymers used in the present work, which is higher than the molecular weight of polymers used in the previous works. The crystallization kinetics of PHB is strongly influenced by the presence of the elastomeric phase. The degree of crystallinity of PHB/PEP blends decreases with an increase in the PEP content. PHB/ECO blends present degrees of crystallinity that can be considered nearly independent of the ECO content. Differences in the morphology of the crystalline phase were also observed, and these are attributed to the presence of elastomeric phase in the intraspherulitic zone.     

Acid–base polyimide blends for the application as electrolyte membranes for fuel cells

The synthesis and characterization of new acid–base polymer blend membranes for the use in polymer electrolyte membrane fuel cell is presented in this paper. A novel polymeric base is synthesized from 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2-bis [4-(4-aminophenoxy)phenyl] hexafluoropropane and diaminoacrydine hemisulfate where the diaminoacrydine hemisulfate contribute the tertiary nitrogen groups to the polyimide backbone. This base polyimide is blended with a polyimide having sulfonic acid group in the main chain. The sulfonated polyimide is synthesized from 1,4,5,8-naphthalene-tetracarboxylic dianhydride (NTDA), 4,4′-diaminobiphenyl 2,2′-disulfonic acid (BDSA), 2-bis [4-(4-aminophenoxy)phenyl] hexafluoropropane (HFBAPP). Various polyimide blends having different molar ratio of sulfonic acid group and acrydine group are synthesized and they are characterized for thermal stability, ion exchange capacity, water uptake, hydrolytic stability and proton conductivity. All the sulfonated polyimides have good thermal stability and exhibited three-step degradation pattern. With the increase in polymeric base content, IEC decreased as AB-0% (2.0640) > AB-10% (2.0058) > AB-20% (1.8792) > AB-30% (1.5686) > AB-40% (1.2670) > AB-50% (1.1690) > AB-75% (0.9098) and water uptake decreased as AB-0% (34.06%) > AB-10% (32.82%) > AB-20% (24.01%) > AB-30% (20.31%) > AB-40% (12.86%) > AB-50% (9.25%) > AB-75% (8.37%). Proton conductivity of the acid–base polyimide blends at 90 °C are AB-0% (0.197) > AB-10% (0.124) > AB-20% (0.122) > AB-30% (0.088) > AB-40% (0.080) > AB-50% (0.034) > AB-75% (0.025). Polyimide blends showed higher hydrolytic stability than the pure acid polyimide. Between the polyimide blends the hydrolytic stability increased with increase in the base polymer content which is attributed to the increase in ionic crosslink density which reduces the polymer swelling and hence the mechanical stability of the membrane increases.     

Effect of transesterification products on the miscibility and phase behavior of poly(trimethylene terephthalate)/bisphenol A polycarbonate blends

Blends of poly(trimethylene terephthalate)/bisphenol A polycarbonate (PTT/PC) with different compositions were prepared by melt blending. The effect of transesterification on the miscibility and phase behavior of the blends was studied using DSC, DMA, and ¹H NMR. The DMA results revealed a two-phase system with partial miscibility. DSC thermograms of the first heating scan showed a crystallizable system in which addition of PC-phase reduces the degree of crystallinity. However, the cooling and also the second heating scans revealed the complete miscibility of all the blends. It was concluded that annealing at 300 °C (to remove thermal history of the blends) caused the constituents to undergo the transesterification reaction, which changes the blend to a miscible system. The miscibility is due to formation of block copolymers with different block lengths which also suppress the crystallization of the system. The degree of randomness and sequence lengths of the copolymers were determined to analyze the extent of transesterification reaction and structure of the system. It was observed that as the reaction progresses, the degree of randomness increases and the sequence length of the copolymers decreases. Moreover, both increase of reaction time and temperature increased the extent of reaction. The results of DSC and ¹H NMR showed that a small amount of reaction is needed to change this system to a miscible blend.     

Polypyrrole/poly(methylmethacrylate) blend as selective sensor for acetone in lacquer

A film of α-naphthalene sulfonate-doped polypyrrole/poly(methylmethacrylate), PPy/α-NS⁻/PMMA, obtained from solution mixing was successfully used as sensing material for acetone vapor in lacquer with a high degree of selectivity based on electrical conductivity over acetic acid and a high degree of stability over the humidity change. Compared with pure PPy/α-NS⁻, the selectivity ratio of acetone/acetic acid response of PPy/α-NS⁻/PMMA blend with a PMMA/PPy weight ratio of 3.0 was ca. 3.9 times higher. The film was found to be insensitive to moisture unless the relative humidity (RH) was lower than 20% RH in which the selectivity ratio of acetone/acetic acid response was enhanced. The time required to reach the equilibrium for acetone exposure was found to increase slightly with increasing humidity.     

共聚物在聚合物共混体系中的增容作用Ⅱ.接枝共聚物和无规共聚物

在不相容的聚合物共混体系中加入共聚物作为增容剂可以有效地改善两相间的界面状况，得到力学性能优良的合金材料。本文主要讨论接枝共聚物和无规共聚物在聚合物共混体系中的增容作用和增容机理。     

Nanocomposites based on a polyamide 6/maleated styrene-butylene-co-ethylene-styrene blend: Effects of clay loading on morphology and mechanical properties

The addition of up to 6% of an OMMT to a 70/30 polyamide 6 (PA6)/maleated styrene-ethylene/butylene-styrene (mSEBS) blend led to ternary compounds where the rigidifying effect of the clay and the toughening effect of the rubber came together. In fact, in the 70/30 blend with 3% OMMT supertough behaviour was accomplished with a modulus increase of 44% with respect to the pure PA6 matrix. When the changes in morphology of the dispersed rubber phase in presence of OMMT are discussed, the slight decrease in viscosity upon clay addition does not explain the increase in rubber particle size that indicates a decrease in the compatibilization level. Interactions between the surfactant of the OMMT and the maleic anhydride groups of modified rubber are proposed as the reason for the decrease in compatibility. The maximum impact strength attained is rather independent of the clay content and the testing temperature. The increase in modulus of the blend upon clay addition was similar to that observed for the pure PA6 matrix, while maintaining the ductile nature in the ternary PN’s, which is not always present in PA6/OMMT binary materials.     

聚甲基丙烯酸甲酯的分子构型对淬火过程中聚偏氟乙烯(PVF_2)β相生成的影响

<正> 聚偏氟乙烯(PVF_2)是一种半结晶聚合物,它至少存在α、β、γ和δ四种晶相结构。其中β相由于其与PVF_2的压电性和热电性直接相关而引起人们的广泛关注。在以前的工作中,我们研究了超速淬火对PVP_2晶相结构的影响。本工作用傅里叶变换红外光谱(FTIR)技术研究了聚甲基丙烯酸甲酯(PMMA)分子构型对淬火过程中PVF_2β相生成温度的影响.