腈纶短纤维线密度测定方法对比分析

运用数理统计方法,对手梳中段称重法和振荡法测定腈纶短纤维线密度进行了对比分析。结果表明:两种方法测定腈纶短纤维的线密度的数据分布均匀,符合正态分布,其平均值和方差存在显著性差异,两种方法不能互相代替;手梳法测定腈纶的线密度耗时长,过程复杂,而振荡法则耗时短,过程简单;建议采用振荡法测定腈纶短纤维的线密度。     

基于 Taguchi 法的注塑制品成型收缩率最小化

运用Taguchi实验设计技术研究了熔体温度、冷却时间、保压压力、注射时间等工艺参数对聚丙烯(PP)碱性蓄电池壳注塑制品成型收缩率的影响,获得了使制品的成型收缩率最小的优化工艺参数。研究表明,在所选择的工艺参数中,对成型收缩率的影响程度按大小排序依次为熔体温度、冷却时间、保压压力、注射时间。所预测的优化工艺组合的最小成型收缩率为0.916%,与验证实验值0.908%较为吻合。     

相容剂对聚丙烯/聚酰胺体系界面张力的影响

采用断裂纤维丝线法和变形液滴回缩法两种方法相结合,在线观察聚酰胺6(PA6)液滴在聚丙烯(PP)中的回缩过程,研究不同相容剂对该体系界面张力的影响。结果表明,PA6液滴在剪切场下发生变形,然后在界面张力的作用下逐渐回缩成球形,并测得该体系的界面张力为7.16 mN/m。添加相容剂可以显著降低体系的界面张力。不同相容剂[聚丙烯接枝马来酸酐(PP-g-MA)、聚丙烯接枝丙烯酸(PP-g-AA)、氢化苯乙烯-丁二烯-苯乙烯嵌段共聚物(SEBS)]对体系界面张力影响不同,满足以下关系:γ_(PP/PA6)>γ_(PP/SEBS/PA6)>γ_(PP/PP-g-AA/PA6)>γ_(PP/PP-g-MAH/PA6)。     

纳米技术在阻燃聚丙烯中的研究进展

综述了纳米无机阻燃剂在阻燃聚丙烯(PP)中的研究进展,主要包括 PP/纳米级金属氢氧化物复合材料、PP/碳纳米管复合材料、PP/蒙脱土纳米复合材料和 PP/POSS 纳米复合材料。     

醇酸树脂、氯化聚丙烯与二甲苯三元体系相图的研究

考察不同二甲苯含量时,醇酸树脂、氯化聚丙烯与二甲苯混合液的分层情况,测定其分层一中各成分的组成,作出三元体系相图,从而更全面地了解醇酸树脂、氯化聚丙烯和二甲苯三者的相容性。     

氯化聚丙烯接枝马来酸酐的研究

为了进一步提高氯化聚丙烯接枝马来酸酐的接枝率,优化工艺条件和不同组分的用量,采用正交实验法,研究了马来酸酐(MAH)用量、引发剂过氧化苯甲酰(BPO)用量、反应温度和反应时间对氯化聚丙烯接枝马来酸酐接枝率的影响。结果表明,引发剂BPO用量对接枝率的影响最为明显,而反应时间相对最弱。4种因素的极差递减顺序为:引发剂BPO用量、MAH用量、反应温度和反应时间。     

Solvent resistance and mechanical properties in thermoplastic elastomer blends prepared by dynamic vulcanization

Dynamic vulcanization was used to prepare thermoplastic elastomer blends of nylon (polyamide), polypropylene (PP) and polybutylene terephthalate thermoplastics with chlorobutyl (CIIR) and nitrile (NBR) rubbers. Mechanical properties of the blends were correlated against composition. Although hardness and tensile strength increase with increasing thermoplastic content for all blends, elongation at break values initially decrease and then increase in the range of 20–40% thermoplastic. For various blend compositions, the swelling behavior was evaluated with solvents that are able to dissolve the uncured rubber portion but not the thermoplastic component of the mixtures. All five systems showed swelling index values that were substantially less than the calculated “theoretical” values of swelling index. This was attributed to a caging effect of the thermoplastic component on the rubber phase, which restricts access of solvent and swelling of the rubber phase. In turn, this affects the solvent resistance of the blend. Some of the blends were evaluated by differential scanning calorimetry to assess the compatibility of the components in the blend. scanning electron microscopy was also used to determine the degree of compatibility of the two phases generated in the mixing process. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Crystalline morphology and dynamical crystallization of antibacterial β‐polypropylene composite

The crystalline morphology and dynamical crystallization of antibacterial polypropylene composite and pure polypropylene were investigated via differential scanning calorimeter (DSC), wide angle X‐ray diffraction (WAXD), and real‐time hot‐stage optical microscopy (OM). The results reveal that the crystalline morphology of antibacterial PP composites changes with variations of the crystallization conditions and compositions. The crystalline phase consists of both α‐PP and β‐PP crystals. The content of β‐PP decreases with the increase in antibacterial agent content and cooling rate. With the addition of β‐nucleating agent, the morphologies of all dynamically crystallized antibacterial PP composites show no obvious spherulitic morphology, and the decrease of crystal perfection and the increase of nucleation density of antibacterial PP composite system could be observed. With the increase of antibacterial agent content, the overall crystallization rates of the antibacterial PP composite increase dramatically, while the content of β‐PP in all antibacterial PP composite decrease distinctly under given cooling conditions. These results can be explained by the interruptive effect of antibacterial agent on interactions of β‐nucleating agent components and the obstructing effect of antibacterial agent on the mobility of PP chains in melts. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

SEBS对SBR/PP热塑性弹性体增容作用的研究

以氢化苯乙烯-丁二烯-苯乙烯嵌段共聚物（SEBS）作为丁苯橡胶（SBR）/聚丙烯（PP）热塑性硫化胶（TPV）的增容剂,研究增容剂对共混体系的力学性能、共混物硫化交联网络结构、熔融温度以及断面形貌的影响。结果表明,SEBS添加量为6份时,体系的综合力学性能最佳;SEBS的加入提高了有效共硫化程度。增加了体系的化学交联密度;随着SEBS用量的增加,TPV的熔融温度逐渐下降;扫描电镜图片显示SEBS能有效提高界面结合力,提高PP与SBR的相容性。     

聚丙烯/蒙脱土纳米复合材料的制备与性能研究

以马来酸酐接枝低分子量聚丙烯为相容剂,采用双螺杆挤出机熔融挤出法,制备插层型聚丙烯/有机钠基蒙脱土、聚丙烯/酸化有机化钠基蒙脱土、聚丙烯/钠基蒙脱土3种纳米复合材料,发现有机钠基蒙脱土、酸化有机化钠基蒙脱土和钠基蒙脱土对PP力学性能和燃烧性能均有一定程度的提高。经X射线衍射(XRD)和扫描电子显微镜(SEM)观察,发现有机钠基蒙脱土片层间距增幅最大,复合材料的燃烧性能也有很大提高。