The effect of shear controlled orientation in injection moulding on the mechanical properties of an aliphatic polyketone

This article relates to an investigation of injection moulding a new commercial polymer, an aliphatic polyketone (PK). A terpolymer and a 30% glass-filled grade were used as study materials together with an isotactic polypropylene that was used as a basis for comparison. Both conventional injection moulding and shear-controlled orientation injection moulding (SCORIM) were employed in processing. Tensile testing was carried out at 80°C as well as at room temperature. Polarized light microscopy and wide-angle x-ray diffraction were used in the characterization of the mouldings. An increase of up to 30% in Young's modulus and 35% in ultimate tensile strength, and a 70–90% increase in strain at peak were gained for the terpolymer (PK) at room temperature, as a result of SCORIM processing. A substantial improvement at 80°C was also recorded for unfilled SCORIM PK mouldings, and is attributed to the pronounced molecular alignment that was induced in SCORIM mouldings, as shown by Debye patterns. It is notable that the SCORIM mouldings of PK exhibit a greater tensile strength at 80°C than the SCORIM mouldings of isotactic polypropylene at 23°C. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys, 35: 415–430, 1997     

钯-稀土催化一氧化碳和苯乙烯交替共聚反应

 利用稀土钇盐或钕盐和乙酸钯组成的催化体系催化一氧化碳和苯乙烯共聚,合成了聚(1-氧代-2-苯基丙撑). 用元素分析、红外光谱、示差扫描量热、热重分析及X射线光电子能谱(XPS)等方法对共聚产物进行了表征. 测试结果表明,共聚物为一氧化碳和苯乙烯的线性交替共聚产物,其玻璃化温度为235 ℃,熔点为250 ℃,分解温度为325 ℃,且用XPS未检测到聚合物中含有残留的金属. 同时考察了催化剂组分2,2′-联吡啶、对甲苯磺酸和对苯醌及溶剂甲醇等的用量对共聚反应的影响,并对聚合反应条件进行了优化. 在优化的反应条件下稀土与钯组成的复合催化剂对一氧化碳和苯乙烯交替共聚的催化活性可达1200 g/(g·h).     

钯（Ⅱ）／2，2′－联吡啶催化一氧化碳和苯乙烯的交替共聚反应

利用乙酸钯和２，２′－联吡啶组成的催化剂体系催化一氧化碳和苯乙烯交替共聚制备聚（１－氧代－２－苯基丙撑），考察了组成催化剂的２，２′－联吡啶和对甲苯磺酸与钯（Ⅱ）的摩尔比对催化活性的影响，同时考察了甲醇用量、溶剂、反应温度和时间等对该催化反应的影响     

The use of etching techniques to investigate the morphology of mechanically induced transformations in an aliphatic polyketone

Existing permanganic etching techniques have been adapted for an aliphatic polyketone terpolymer to examine its spherulitic and lamellar morphology by Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). A spherulitic morphology was observed consisting of irregularly shaped spherulites with an average diameter of 5–7 μm and poorly defined spherulite boundaries. Crystalline lamellae were found to be oriented radially within the spherulites. The morphology associated with mechanically induced transformations in a number of deformation systems has been studied and compared to that arising in other common polymeric systems. Changes in morphology through the neck region of drawn samples revealed the elongation of the spherulites as the morphology is transformed from a spherulitic to a fibrillar structure. In samples tested between 23°C and 120°C, radial flaws were observed within the spherulites prior to and within the neck transformation zone. These radial flaws were not observed for samples tested at higher temperatures. Four-point bend tests were conducted on double notched and pre-cracked aliphatic polyketone samples. Examination of the process zone around the crack at the core of the sample revealed crazes characteristic of semicrystalline polymers subjected to a highly constrained stress state. However, the process zone around the crack at the surface of the sample was found to consist of shear bands, suggesting a less constrained damage regime. High cycle fatigue loading also induced flaws oriented radially within the spherulites. Examination of the region around the failure surface in samples fatigue cycled until failure revealed a process consisting of an array of crazes reminiscent to that found in the four-point bend tests. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 3246–3255, 1999