云母与成核剂复配改性PP

采用云母和成核剂填充改性聚丙烯(PP),研究了复合材料的力学性能、结晶性能及耐热性能。结果表明:云母可有效提高PP的弯曲强度及模量、悬臂梁缺口冲击强度和耐热性能;少量成核剂NA11和表面活性剂硬脂酸钙可使PP/云母复合材料的拉伸强度、弯曲强度、弯曲模量及悬臂梁缺口冲击强度较纯PP分别提高10.4%,32.9%,92.6%,9.2%,热变形温度由纯PP的105℃提高到135℃;云母及NA11对PP具有异相成核作用,复合材料的结晶温度明显提高,晶粒细化、致密。     

β成核剂改性玻纤增强PP复合材料的性能

研究了玻璃纤维(GF)和β成核剂对GF增强聚丙烯(GFRPP)复合材料力学性能的影响。复合材料的拉伸强度及模量均随GF含量的增加而增加,而拉伸断裂应变随GF含量的增加而减小。β成核剂诱导生成β晶型,提高了复合材料的冲击强度,在β成核剂质量分数为0.05%时,所有GFRPP复合材料的冲击强度均达到最大值。β成核剂质量分数为0.20%,w(GF)为30%的试样综合力学性能最优,其拉伸强度达到39.04 MPa,冲击强度为7.21kJ/m~2。GF对β成核剂具有抑制作用。添加β成核剂改变了基体的晶型,使试样更加柔软,有利于提高冲击强度。     

β成核剂改性PP力学性能与结晶性能的研究

使用X射线衍射仪(XRD)和差示扫描量热仪(DSC)研究了β成核剂(CHJ1和CHJ2)对聚丙烯(PP)结晶性能和力学性能的影响。结果表明:CHJ1是一种高效的β晶成核剂,β晶相对含量可达74%~88%,其可使PP的结晶温度向高温方向偏移;CHJ1的加入提高了PP的冲击性能和热变形温度,其简支梁冲击强度可提高2.5倍,热变形温度最高可达109℃,添加质量分数0.1%CHJ1的PP可应用于锂电池隔膜的成型。     

PP复合成核剂的研究进展

综述了用于丙烯聚合的α成核剂(山梨醇衍生物类、有机磷酸盐类、松香类等)和β成核剂复合化的研究进展.成核剂的复合化主要是现有成核剂通过化学改性实现多功能化、不同成核剂之间的相互协同以及成核剂与其他助剂的协同.     

HYBRAR与α成核剂对PP性能的影响

将高性能热塑性弹性体苯乙烯、乙烯支化异戊二烯三嵌段共聚物（HYBRAR）及α成核剂与PP进行共混,并参照各测试标准制备试样。对共混物的力学性能及热稳定性进行了表征。研究结果表明,HYBRAR的加入使共混物的冲击强度和断裂伸长率显著提高,而拉伸强度降低,α成核剂的加入使得PP及PP／HYBRAR共混物的冲击强度和拉伸强度升高;α成核剂提高了共混物的热稳定性,而HYBRAR降低其热稳定性。     

不同成核剂对聚丙烯材料结晶形态及性能的影响

主要通过运用偏光显微镜、X射线衍射仪及力学性能测试等手段研究了不同成核剂在不同添加量时对聚丙烯材料的结晶形态及力学性能造成的影响。结果表明:不同晶型的成核剂会对聚丙烯材料产生不同的影响,使材料形成不同晶型的球晶,其力学性能也会产生不同的变化。     

成核剂在聚丙烯(PP)改性中的作用

本文通过分析PP分子的结晶过程,介绍了太核剂对PP成核作用的原理以及加入成核剂对PP性能的影响,分析了成核剂在PP产品加工中的重要作用。     

成核剂改性聚丙烯研究进展

目前工业化生产的聚丙烯（PP）通常存在热性能、电性能、光学性能等较差的缺点,特别是在低温或高应变速率等极端条件下,通常可以通过添加成核剂改善这些问题。PP成核剂可以诱导PP异相成核,使PP的结晶构造进一步细微化,即提高结晶度、降低球晶的直径,进而改进PP的各项性能。从PP成核剂的种类开始叙述,介绍了不同种类的α晶型成核剂（无机类、有机类）和β晶型成核剂（无机类、稠环芳烃类、稀土化合物等）及各自的特点,在此基础上综述了近年来的PP成核剂,并总结了它们对于PP各项性能的改性效果。最后结合PP成核剂的实际应用对PP成核剂的研究方向进行了展望。     

不同成核剂成核聚丙烯的结晶行为与力学性能

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。     

β晶型成核剂改性聚丙烯纤维研究

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。     

β晶型成核剂对PP结晶行为的影响

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。     

熔融非敏感型成核剂在聚丙烯加工中的应用研究

分别将熔融非敏感型成核剂A、成核剂B及通过特殊工艺处理后的混合成核剂(A+B)按添加质量分数0.08%,在加有其他助剂的情况下,分别与一定质量的超高流动均聚聚丙烯(PP)、高流动抗冲共聚PP、中流动丙丁无规共聚PP混合均匀,经双螺杆挤出造粒机熔融挤出、造粒,制得不同PP树脂,并对PP树脂的力学性能、光学性能、结晶行为及结晶形态进行研究。结果表明:与未添加熔融非敏感型成核剂的同牌号PP树脂相比,添加熔融非敏感型成核剂后,同牌号PP树脂的弯曲模量和拉伸屈服强度均得到提高。其中,超高流动均聚PP的弯曲模量最大提高了41.9%,拉伸屈服强度最大提高了13.2%;高流动抗冲共聚PP弯曲模量最大提高了48.7%,拉伸屈服强度最大提高了12.4%;中流动丙丁无规共聚PP弯曲模量最大提高了25.2%,拉伸屈服强度最大提高了14.2%。3种PP树脂的熔体质量流动速率、简支梁缺口冲击强度、模塑收缩率保持不变。熔融非敏感型成核剂的加入,提高了PP树脂的白度、光泽度,以及热变形温度和结晶温度,较大改善了PP树脂的黄色指数和雾度,显著降低了PP树脂的半结晶时间。熔融非敏感型成核剂(A+B)对超高流动均聚PP、高...     

成核剂对聚丙烯部分力学性能的改善分析

在聚丙烯中以比例2%分别加入有机磷酸酯类的成核剂611,612,613,NA-11和0629C-3,观察了样品脆断面的结构情况,测试了成核剂加入前后样品力学性能的改变,并就改变的原因进行了分析;同时,也对在样品中加入1%成核剂0629C-3的结果与加入2%的结果进行了比较。     

Characterization of modified polypropylene by scanning electron microscopy

Characterizing the morphology of modified multiphasic polymer systems, as are often applied for improving the impact strength, is normally a complicated and tedious task. Nevertheless, knowledge about the volume fraction and particle‐size distribution of the elastomer phase is important for the specific development of high‐impact systems. Direct production in the reactor enables only indirect control of these two quantities. Computer‐controlled scanning electron microscopy in combination with image processing allows an automated measurement of both all the necessary particle parameters (size distribution, shape, orientation, etc.) and the elastomer content of the material. Since bulk materials are used for the investigation, additionally, three‐dimensional information about the structure of the material can be gained by simply varying the electron energy, without the necessity to resort to multiple slices. This information is especially important in the case of particles with extremely irregular shapes, as obtained, for example, by strong agglomeration of the modifier particles. The mathematical routines used for calculation of the particle‐size distributions from the measured profile‐size distributions cannot be applied in such cases. The method was tested for several materials with significantly different compositions, both immediately after molding and also after a subsequent thermal relaxation. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1152–1161, 2000     

Properties of glycerin‐thermally modified wood flour/polypropylene composites

This study aimed to investigate the combination effect of glycerin treatment and thermal modification of wood flour on the physical, mechanical, thermal dynamic mechanical properties of wood flour/polypropylene (PP) composite. The morphological aspect was also investigated. The wood flour was first impregnated in the aqueous solution of glycerin, followed by heat treatment at 200°C for 1 h. Then the unmodified or modified wood flour was blended with PP at a weight ratio of 4:6 to prepare composites. Moisture adsorption experiment and X‐ray photoelectron spectroscopy analysis of wood flour demonstrated that the hygroscopicity and the free surface hydroxyl groups of wood flour decreased after glycerin‐thermal modification. Thickness swelling of the 10% wt glycerin‐thermally modified wood flour/PP composite was reduced by 42.8% after 96 h immersion as compared to unmodified control. Evaluation of mechanical properties in impact and flexure modes indicated that glycerin treatment alone had no significant effect, but the combination of glycerin and thermal treatment slightly decreased the strength, with the exception of 10% glycerin and heat modified sample. Dynamic mechanical analysis and scanning electron microscope illustrated the improved interfacial bonding between PP and wood flour modified by 10% glycerin and heat treatment. POLYM. COMPOS., 35:201–207, 2014. © 2013 Society of Plastics Engineers     

苯乙烯接枝改性聚丙烯制备及其性能

以过氧化苯甲酰为引发剂,采用反应挤出法将苯乙烯(St)接枝到等规聚丙烯(iPP)上,并考察了St浓度对接枝PP结晶性能、流变性能和发泡性能的影响。由FTIR、GPC和MFR表征结果表明St成功接到PP上;DSC结果表明,接枝PP结晶峰值温度与iPP相比最大提高了15.4℃;由剪切流变测试结果,在低频区,接枝PP的G'值增大,出现明显的剪切变稀现象,tan δ-ω曲线中出现平台,说明接枝PP中有长支链结构的存在;由于接枝PP的熔融流动速率降低即熔体强度提高,使得接枝PP的泡孔更规则。     

Crystallization and melt behavior of magnesium hydroxide/polypropylene composites modified by functionalized polypropylene

The crystallization and melting behavior of Mg(OH)₂/polypropylene (PP) composites modified by the addition of functionalized polypropylene (FPP) or acrylic acid (AA) and the formation of in situ FPP were investigated by DSC. The results indicated that addition of FPP increased crystallization temperatures of PP attributed to the nucleation effect of FPP. The formation of in situ FPP resulted in a reduced crystallization rate, melting point, and degree of crystallization because of the decreased regularity of the PP chain. For the Mg(OH)₂/PP composites, addition of Mg(OH)₂ increased the crystallization temperatures of PP attributed to a heterogeneous nucleation effect of Mg(OH)₂. Addition of FPP into Mg(OH)₂/PP composites further enhanced the crystallization temperatures of PP. It is suggested that there is an activation of FPP to the heterogeneous nucleation effect of Mg(OH)₂ surface. The addition of AA also increased the crystallization temperatures of PP in Mg(OH)₂/PP composites, but crystallization temperatures of PP were not influenced by the AA content, a phenomenon explained by the heterogeneous nucleation effect of the Mg(OH)₂ surface activated by FPP and AA. A synergistic effect on crystallization of PP in Mg(OH)₂/PP composites further increased the crystallization temperatures of PP. However, the crystallization temperatures of Mg(OH)₂/PP composites modified by in situ FPP were lower than those of Mg(OH)₂/PP composites modified by the addition of FPP or AA. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91:3899–3908, 2004     

丙烯酸改性卤锑阻燃聚丙烯的结晶性能

研究了丙烯酸(AA)改性Sb2O3,聚丙烯(PP)母料制备的不同用量卤锑阻燃PP。阻燃PP的差示扫描量热法结果表明,阻燃剂在PP中存在明显的异相成核作用,使PP结晶温度提高,Sb2O3对PP的异相成核作用比十溴二苯醚明显。在无引发剂过氧化二异丙苯(DCP)存在下,AA对阻燃PP中PP结晶温度的影响取决于阻燃剂的用量;在DCP存在下,PP的结晶温度不随AA用量增加而改变。DCP用量增加导致PP严重降解,结晶温度与熔融温度降低。