通过甲醇溶剂冻胶纺丝制备水溶温度为5-80℃聚乙烯醇（PVA）水溶纤维，采用X射线衍射、双折射、电子强伸仪等测定了PCA水溶纤维的结晶度、取向度、应力应变曲线。讨论了PVA水溶纤维的结构与力学性能的关系。结果表明：纤维的结晶度和取向度随拉伸倍数的增加而增加，拉伸倍数为16时，纤维力学性能良好，纤维结构均匀，水溶温度范围宽。

Highly monodispersed emulsifier-free poly(methylstyrene) (PMS) latex particles were prepared via an emulsifier-free emulsion polymerization in the presence of 2,29-azobis-(2-amidineopropane) dihydrochloride (V-50) as an initiator. A combination of kinetics and molecular weight distribution studies revealed that the polymerization followed the micellization nucleation mechanism. Results showed that an appropriate initiator concentration was necessary to obtain monodisperse and stable latex particles. Conversion of methylstyrene was found to increase significantly with increasing initiator concentrations. However, the size of PMS latex particles decreased with both the increase of initiator concentration and the reaction temperature at a constant ionic strength. The particle size was increased as the ionic strength of the aqueous phase increased, yet the variation of ionic strength had little effect on the particle size distribution. SEM micrographs showed that an agitation rate of 350 rpm or higher was required in order to produce highly monodispersed poly(methylstyrene) latex particles.

目的 研究真空烧结粉末冶金法制作钛合金试件的力学性能。方法 采用真空烧结粉末冶金法制作钛合金试件，测试钛合金试件的抗压强度和弯曲强度。结果 在100-300MPa范围内，烧结体的抗压强度为111-921MPa，随着成形压力的增大，烧结体的抗压强度增大；采用的3种钛粉末粒度对烧结体的力学性能没有影响；钛粉镀铜镀锡组烧结体的抗压强度较其它粉末配方组大。在150～250MPa范围内。烧结体的三点弯曲强度为102～183MPa，弯曲弹性模量为12193～26630；不同配方组的烧结体弯曲强度有差异（P<0.05），而弯曲弹性模量无差异（P>0.05）。结论钛基金属粉末的配方及成形压力对烧结体的力学性能有影响，对钛粉进行化学镀铜镀锝处理是改善钛粉的压制性能、烧结性能。提高烧结体力学性能的理想方法。

A convenient method of preparing ultrafine poly(methylstyrene) (PMS) latex particles with aldehyde groups on the surface is developed. PMS latexes in the size range 33-81nm were prepared via microemulsion polymerization, using cetyltrimethylammonium bromide (CTAB) as surfactant. The surface of the PMS latexes was oxidized in the presence of tert-butyl hydroperoxide catalyzed by copper(Ⅱ) chloride. As the degree of oxidation increased up to 6h, the amounts of aldehyde group increased. Bigger particles were found to have a slightly higher rate of oxidation than small ones under the same oxidation conditions. The particle size underwent little change during oxidation; thus, the amounts of functional groups and the particle size could be controlled concurrently. Dialysis study of the oxidized PMS microlatexes indicated that the instability of highly oxidized PMS microlatexes was caused by the reduction of total surface charge density due to the presence of carboxylic acid groups.

采用电导法、紫外光谱法、GPC和电子显微镜等方法对甲基苯乙烯和苯乙烯的无乳化剂乳液聚合进行了较为详细的研究。探讨了这两种单体在无乳化剂乳液聚合初期的引发成核机理，比较了它们在无乳化剂乳液聚合时的异同。甲基苯乙烯的无乳化剂聚合机理与苯乙烯类似，即采用胶束成核机理聚合。但是，由于甲基苯乙烯有较低的活化能和链增长速率常数，使其在聚合初期有较高的转化率和更加显著的水相终止。所以在相同的条件下，甲基苯乙烯比苯乙烯有较大的胶乳粒子尺寸。