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采用差示扫描量热仪和偏光显微镜研究了高相对分子质量成核剂(PNA)改性聚丙烯(PP)的结晶行为和结晶形态。结果表明,添加PNA后,PP的起始结晶温度(Tc)和结晶峰温(Tp)明显升高,降温速率为5 ℃/min,加入0.7份PNA时,Tc和Tp分别提高到131.90 ℃和128.32 ℃,结晶度由未添加PNA时的56.32 %提高到61.63 %;加入PNA后,球晶数量明显增多球晶尺寸更加细小且均匀,促进了PP的结晶,提高了PP制品的定型温度,能够缩短制品的生产周期。 相似文献
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不同成核剂成核聚丙烯的结晶行为与力学性能 总被引:12,自引:0,他引:12
制备了6种成核剂成核聚丙烯(PP)母料研究了成核母料和成核母料/PP的结晶,熔融行为,力学性能和透明性等物理性能,不同成核在成核母材料和成核母料/PP中对PP的结晶与熔融行为以及性能有不同的作用,观察到成核型A成核PP具有较高的结晶温度与综合性能,而成核剂B成核PP的透明性较好。 相似文献
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高相对分子质量聚丙烯的成核行为 总被引:4,自引:0,他引:4
在反应器内合成了不合成核剂及含有成核剂的高相对分子质量聚丙烯(HMWPP),将其与均聚聚丙烯(F401)混合制备了成核改性的PP。用差示扫描量热计和偏光显微镜分析了混合体系的结晶行为和形态。结果表明,HMWPP可以诱导β晶形成,细化PP球晶,使材料冲击强度增加50%。而成核剂与HMWPP共同作用使PP的结晶温度和结晶速率显著升高,球晶尺寸细化,弯曲模量增加32%,热变形温度提高18℃。 相似文献
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研究了新型分子结构成核剂NX8000、有机磷酸盐成核剂NA-11以及无机纳米粉体二氧化硅对聚丙烯(PP)力学性能、透明性、结晶行为和耐热性能的影响。结果表明:3种成核剂能明显改善PP的拉伸强度,而对其冲击强度没有明显的影响;成核剂NA-11对PP增刚效果显著,NX8000的增透效果显著;3种成核剂都能提高PP的结晶度、结晶温度、熔融峰温度和维卡软化点。 相似文献
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The isothermal and nonisothermal crystallization kinetics of nonnucleated and nucleated isotactic polypropylene (iPP) were investigated by DSC and a polarized light microscope with a hot stage. Dibenzylidene sorbitol (DBS) was used as a nucleating agent. It was found that the crystallization rate increased with the addition of DBS. The influence of DBS on fold surface energy, σe, was examined by the Hoffman and Lauritzen nucleation theory. It showed that σe decreased with the addition of DBS, suggesting that DBS is an effective nucleating agent for iPP. Ozawa's theory was used to study the nonisothermal crystallization. It was found that the crystallization temperature for the nucleated iPP was higher than that for nonnucleated iPP. The addition of DBS reduced the Ozawa exponent, suggesting a change in spherulite morphology. The cooling crystallization function has a negative exponent on the crystallization temperature. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 2089–2095, 1998 相似文献
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In this investigation the effects of a rosin‐type nucleating agent, which was prepared from cocrystallizing of dehydroabietic acid and Na‐dehydroabietate, on polypropylene (PP) crystallization were studied. The results of differential scanning calorimetry and X‐ray diffraction proved that a cocrystal of dehydroabietic acid and Na‐dehydroabietate was formed. The lower melting point of the cocrystal caused it to be uniformly dispersed in PP. When cocrystals were added as nucleating agent, the mechanical properties, heat distortion temperature, and crystallization temperatures of PP were obviously improved, and the size of spherulites was also decreased. This proved that the cocrystals of dehydroabietic acid and Na‐dehydroabietate could act as an effective nucleating agent for PP. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1069–1073, 2002 相似文献
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利用注塑法制备校准和测试样片,根据聚丙烯(PP)中山梨醇缩醛类透明剂成核剂在1 073 cm-1处的特征吸收峰进行定性和定量,建立了用红外光谱法测定PP中山梨醇缩醛类透明剂成核剂含量的方法,克服了制片厚度对测试结果的影响。结果表明,透明剂含量与其特征峰的吸光度呈良好的线性关系,相关系数达 0.999 4,样品中透明成核剂含量测定结果回收率在98.59 %~100.02 % 之间;该方法检测速度快、检测精度高、绿色环保,非常适合于PP中透明成核剂含量的测定。 相似文献
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A novel highly efficient β‐nucleating agent for isotactic polypropylene (iPP), hexahydrophthalic barium (HHPA‐Ba), was found and its effects on the mechanical properties, the β‐phase content, and crystallization behavior of iPP were investigated, respectively. The results show that the β‐phase content of nucleated iPP (kβ value) can reach 80.2% with 0.4 wt % HHPA‐Ba. The impact strength and crystallization peak temperature of nucleated iPP are greatly increased. Compared with pure iPP, the impact strength of nucleated iPP can increase 2.4 times. Meanwhile, the spherulite size of nucleated iPP is dramatically decreased than that of pure iPP. The Caze method was used to investigate the nonisothermal crystallization kinetics of nucleated iPP and the crystallization active energy was achieved by Kissinger method. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
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