共查询到19条相似文献,搜索用时 125 毫秒
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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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成核剂对增韧聚丙烯力学性能的影响 总被引:11,自引:0,他引:11
主要研究成核剂种类及用量对乙烯-辛烯共聚物(POE)增韧聚丙烯(PP)力学性能的影响。研究表明:随着成核剂NA1的加入,PP/POE共混物的透明性、冲击强度、弯曲强度、拉伸屈服强度均明显提高,研制的改性PP的透明性、韧性和刚性得到了平衡。 相似文献
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研究了成核剂对PP/POE共混物的力学性能和结晶行为的影响。加入成核剂提高了共混物的冲击强度和弯曲模量,使PP/POE共混物的刚性韧性得到了很好的平衡,同时,成核剂提高了PP/POE共混物的结晶速率和结晶温度,减小了球晶的尺寸,有利于力学性能的提高和缩短加工时间。 相似文献
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在均聚聚丙烯(PPH)、无规共聚聚丙烯(PPR)和嵌段共聚聚丙烯(PPB)中分别加入刚性成核剂,研究其对聚丙烯(PP)结构与性能的影响。利用电子万能试验机、差示扫描量热仪(DSC)、傅立叶红外光谱仪(FT-IR)和偏光显微镜(POM)等表征手段对改性PP的力学性能、微观结构和结晶性能进行了研究。结果表明,刚性成核剂有细化球晶和加快结晶速率的作用;同时能有效提高PP的弯曲模量、冲击强度、热变形温度;添加0.2份刚性成核剂的PPH和PPB以及添加0.3份刚性成核剂PPR的综合性能最佳。 相似文献
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β成核剂对嵌段共聚聚丙烯力学性能的影响 总被引:2,自引:0,他引:2
研究了一种稀土类β成核剂对嵌段共聚聚丙烯(PP-B)结晶行为以及力学性能的影响。结果表明:PP-B的总结晶度随成核剂用量的增加而增加,其中的α晶结晶度先下降后上升,β晶结晶度先上升后下降,转折点在成核剂含量0.05%左右。随着成核剂用量的增加,聚丙烯的球晶尺寸明显下降,冲击强度先大幅度上升然后下降;拉伸强度、弯曲强度、弯曲模量和维卡软化温度先下降后上升。 相似文献
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β晶型成核剂对PP结晶行为的影响 总被引:1,自引:0,他引:1
制备了β晶型聚丙烯(β-PP),利用广角X射线衍射仪与偏光显微镜表征了球晶形态,研究了其非等温结晶行为,并用Jeziorny法、莫志深法和Kissinger法对所得数据进行处理。结果表明,添加β晶型成核剂后,PP由α晶型向β晶型转变,起始结晶温度明显提高,总结晶时间缩短,结晶活化能降低。β-PP的Avrami指数在1.69~1.89,小于PP,表明β晶型成核剂的加入改变了PP的成核机理及生长方式。 相似文献
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O.J. Nguon Z. Charlton M. Kumar J. Lefas G.J. Vancso 《Polymer Engineering and Science》2020,60(12):3046-3055
The thermal properties of a sorbitol-type nucleating agent (viz. 1,2,3-trideoxy-4,6:5,7-bis-O-[(4-propylphenyl)methylene]-nonitol (TBPMN)) were examined in this study, and the influence of common processing additives assessed. In addition, we describe a novel approach to monitor in situ the self-assembly of the nucleator in presence of additives by optical microscopy. The performance of sorbitol compounds is closely associated to their chemical structure and ability to self-assemble. TBPMN formed elongated fibrils from the melt under inert atmosphere, in molted polypropylene, or in presence of antioxidants. However, calcium stearate (CaSt) and glycerol monostearate hampered growth, and yielded thinner fibrils. In presence of the additives, melting point depression of the nucleator occurred, and resulted in a lower degree of crystallinity upon cooling. Performance evaluation of the nucleator in polypropylene blends revealed an increased crystallization temperature when antioxidants were present, while CaSt inhibited nucleator activity. The effect of mono-glycerides was found highly dependent on the processing conditions. Noteworthy, blends containing all the additives displayed the highest performance. This study highlights the importance of the preparation method of polymer additive blends to achieving the best performance in the final product. Characterization was performed by thermogravimetric analysis, Fourier-transform infrared spectroscopy, optical microscopy, and differential scanning calorimetry. 相似文献
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β晶型成核剂改性聚丙烯纤维研究 总被引:4,自引:1,他引:4
研究了含 0 .2 5 %β晶型成核剂 (酰胺化合物 )的聚丙烯 Z3 0 S及其纤维的力学性能、晶型结构和微观形态。通过纺丝 -拉伸实验和力学性能测试、广角 X射线衍射分析、SEM观察 ,发现成核改性后生成了β晶型聚丙烯 (K值约为 75 .3 % ) ,抗冲性能大幅度提高。β晶型聚丙烯在纺丝卷绕过程中发生了β晶型→α晶型转变 ,纤维中产生约 10 %微孔隙 ,改性纤维的力学性能有所降低。 相似文献
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Polypropylene (PP)/tetrapod‐shaped zinc oxide whisker (T‐ZnOw) composites are prepared via a melt‐mixing method in combination with a Haake rheometer. Differential scanning calorimetery (DSC) is used to investigate the nonisothermal and isothermal crystallization behaviors of the composites. Crystalline morphology is observed using hot‐stage optical microscopy, and the mechanical performance of the composites is investigated. Results indicate that T‐ZnOw has no heterogeneous nucleation effect on PP; in fact, it retards the growth of the crystal. Filled T‐ZnOw in PP matrix decreases the peak crystallization and melting temperatures of PP. T‐ZnOw shows either a reinforcing or toughening effect on the PP matrix at very lower weight ratios. These effects, however, decline with increasing T‐ZnOw contents because the size of the spherulitic crystals becomes bigger. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
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This article concerns a detailed mechanistic investigation of the directional entrapping modification on the polypropylene (PP) surface, when stearyl-alcohol poly(ethylene oxide) ether (AEO) was applied as the modifier. The results of swelling degree and contact angle are found to exhibit similar evolutions as functions of swelling temperatures and swelling time, revealing that the modifier implantation is closely related to the swelling level of swollen PP. A solvent-induced crystallization (SINC) and a subsequent crystalline collapse are indicated to occur during surface swelling. Both the amorphous regions on PP surfaces and the microvoids induced by SINC are suggested to contribute to surface swelling and to provide embedding sites for modifier implantation. XRD and DSC analyses reveal a considerably homogeneous distribution of the stearyl segments of AEO in modified surfaces and confirm that the stearyl chain is partially compatible with PP. A thermodynamically stable phase-mixed structure of modified PP is proposed. The mechanistic investigation gives comprehensive insights into the directional entrapping modification and is significant for the extensive applications of the entrapping method for semicrystalline polymers. 相似文献
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Talc‐filled polypropylene (PP) composites coupled with silane‐grafted polypropylene (PP‐g‐Si) were prepared. Effect of PP‐g‐Si on the mechanical properties, crystallization, and melting behavior of PP composites was investigated. Compared with the uncoupled composites, the mechanical properties of Talc/PP composites coupled with a small amount of PP‐g‐Si were increased to some extent. Meanwhile, PP‐g‐Si can promote crystallization rate and increase crystallization temperature of PP in the composites. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2974–2977, 2000 相似文献
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Combined effect of α‐nucleating agent (NA) sodium 2,2′‐methylene‐bis(4,6‐di‐tert‐butylphenyl) phosphate (NA11) and nanoclay (NC) on the mechanical properties and crystallization behavior of isotactic polypropylene (iPP) was investigated by mechanical testing, wide‐angle X‐ray scattering (WAXD), differential scanning calorimetry (DSC), polarized optical microscopy (POM), and scanning electron microscopy (SEM). The mechanical testing results indicated that the separate addition of NA11 and NC only increased the stiffness of iPP while the combined addition of NA11, NC, and maleic anhydride grafted polypropylene (PP‐g‐MA) simultaneously improved stiffness and toughness of iPP. Compared to pure iPP, the tensile strength, the flexural modulus, and impact strength of iPP composites increased 9.7, 38.6, and 42.9%, respectively. The result indicated good synergistic effects of NC, NA11, and PP‐g‐MA in improving iPP mechanical properties. WAXD patterns revealed NA11, and NC only induced the α‐crystals of iPP. SEM micrograph showed that the PP‐g‐MA could effectively improve the dispersing of NC in iPP. Finally, the nonisothermal crystallization kinetics of neat iPP and PP nanocomposites was described by Caze method. The result indicated that the addition of NA overcame the shortcoming of low crystallization rate of NC nanocomposites and maintained the excellent mechanical properties, which is another highlight of the combined addition of NAs and nanoclay. Meanwhile, the result showed that nuclei formation and spherulite growth of iPP were affected by the presence of NA and nanoclay. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献