聚苯醚砜注射成型

介绍耐高温热塑性工程塑料聚苯醚砜树脂的注射成型设备、模具和注射工艺等。     

Aromatic-aliphatic copolyesters: structure and properties

Aromatic-aliphatic copolyesters synthesized by interfacial polycondensation were characterized by differential scanning calorimetry. X-ray diffraction and density measurements. A decrease in the T_g and melting temperature was observed on increasing the glycol content of the copolyesters. The wholly aromatic polyesters showed changes both in the Bragg angle position and intensity of the reflections, whereas in the aromatic-aliphatic copolyesters no sharp change was observed.     

Radical copolymerization of sulphur dioxide and styrene: 4. Intramolecular excimer formation in poly(styrene sulphone)s

Intramolecular excimer formation in poly(styrene sulphone)s with various compositions has been investigated based on the characteristic monomer sequence distributions which were determined experimentally. The fluorescence spectra of the poly(styrene sulphone)s show two emission bands at 285 nm and 330 nm as for polystyrene, corresponding to the monomer and the excimer bands, respectively. The ratio of the excimer to the monomer emission intensities (I_e/I_m) is linearly correlated with the mole fraction of styrene. This observation is a consequence of the characteristic sequence distributions in poly(styrene sulphone)s. containing a very small fraction of SMS units (S = SO₂; M = styrene). The efficiency of excimer formation in poly(styrene sulphone)s with regular styrene sequences, e.g. dyad sequence only, was calculated from the sequence distribution and empirical I_e/I_m. It is concluded that the excimer formation in poly(styrene sulphone)s is very efficient. Energy migration along the copolymer chain was also demonstrated by measuring the degree of polarization as a function of copolymer composition. The efficient excimer formation and the depolarization in poly(styrene sulphone)s suggest that the SO₂ unit in poly(styrene sulphone)s does not act as a barrier or trap to energy migration unlike the methyl methacrylate unit.     

Curing of bismaleimides: 3. Effect of structure on thermal behaviour of bis(amide-maleimide)

This paper describes the synthesis and characterization of six bismaleimide resins containing amide linkages in their backbones. The effect of structure on thermal behaviour was investigated by introducing phosphine oxide, fluorene, ether, methylene, m-phenylene and sulphone groups into the backbone. Thermal characterization of these bismaleimides was achieved using differential scanning calorimetry and thermogravimetric analysis. The presence of an electron withdrawing group in the backbone of the bisimide increased the curing temperature and reduced the reactivity of the maleimide bond. Thermal stability of the cured bismaleimide resins depended on their structure and it was found that the phosphorus and fluorene containing bisimide resins gave high char yields.     

Polycondensation kinetics of poly(phenylene ether sulphone)

The synthesis of poly(phenyl ether sulphone) (from the potassium salts of 4,4′-dihydroxydiphenyl sulphone and 4,4′-dichlorodiphenyl sulphone or 4-chloro-4′-hydroxydiphenyl sulphone) was found to have different reaction kinetics according to the route used. By discriminating between rate constants (between monomer/monomer, monomer/polymer, polymer/polymer) a set of multi-parameter kinetic equations is obtained. Experimental and simulated values of the individual rate constants were in good agreement (for both the reaction rate and molecular weight distribution). The polycondensation reaction can be analysed, in terms of the component reactions.     

新型聚醚砜超滤膜的制备与表征

以聚醚砜(PES)为膜材料,N,N-二甲基乙酰胺(DMAc)为溶剂,聚乙二醇(PEG)和二氧化钛(TiO2)为添加剂,采用相转化法制备聚醚砜超滤膜.研究了不同铸膜液配方所制备的超滤膜的性能.考察了添加剂的种类及含量对膜性能的影响.对所制备的聚醚砜超滤膜的孔径、孔隙率及耐污染性进行了表征,并通过SEM观察了膜表面与断面形态.用PEG-400和TiO2作混合添加剂所制得的聚醚砜超滤膜纯水通量可达148 L/(m2.h),对胃蛋白酶的截留率可达56%.     

耐高温的聚硫醚砜和聚硫醚酮

综述了聚硫醚砜,聚硫醚酮的性能,制造工艺,介绍了应用领域。     

电化学氟化法制备全氟丁磺酸钾

本文分别介绍了以环丁烯砜或丁磺酰氯为原料经电解氟化等过程制取全氟丁磺酸钾的方法。首先，二种原料各自在Simons电解槽中转变为全氟丁磺酰氟，然后将生成的酰氟除酸分离提纯，再与氢氧化钾水溶液反应，过滤和干燥由碱解反应生成的沉淀物，便制得最终产品。此外，本文还对采用这两种原料制成最终产品工艺路线的优缺点进行了比较。     

聚芳醚砜改性研究的进展

本文综述了近年来聚芳醚砜改性研究的进展，着重介绍了氰酸根、氨基、乙炔基、乙烯基、丙烯基、烯丙基、环氧基、马来酰亚胺基，以及氰基等活性基团作为封端基或侧基的聚芳醚砜的合成及应用。     

Effect of temperature on the friction and wear of heat-resistant polymer-based composites

The friction and wear of polyether sulphone (PES: ‘Victrex’-ICI), polyether etherketone (PEEK: ICI), polyamide-imide (PAI: Torlon'-Amoco) and Polytetrafluoroethylene (PTFE) composites were measured at a constant sliding speed and under a constant load at various temperatures up to 300 °C by rubbing against a steel disc. The frictions of the composites, except for some PAI composites, were generally little dependent upon temperature over a wide range of temperature. PTFE filler was effective in reducing the wear of composites at high temperatures. However, the addition of various fibres to the composites was not effective at high temperatures. The wear of PAI composites increased rapidly with increasing temperature and thus their temperature variations were considerably greater than those of the other composites. The wear of PTFE containing ‘Econol’ E–1 OI, a polyoxybenzylene nomo-polymer (Sumitomo Chemical Co.) and graphite was similar to that of the PEEK composite containing PTFE, and their wear rates were remarkably low over a wide range of temperature. The wear-reducing mechanisms of PTFE and ‘Econol’ fillers are discussed on the basis of microscopic examinations of the frictional surfaces.