工艺参数对聚丙烯/聚酰胺6共混材料WAIM管件性能及微观形态的影响

基于自行搭建的水辅助注射成型(WAIM)实验平台对聚丙烯/聚酰胺6（PP/PA6）共混材料进行WAIM实验,探究工艺参数对PP/PA6共混材料的WAIM管件的残余壁厚、表观质量及力学性能的影响,并进行了微观形态观测。结果表明,随着熔体温度、模具温度和注水压力的增加,塑件残余壁厚逐渐减小;随着注水延迟时间的增加,塑件残余壁厚逐渐增大;随着模具温度、注水延迟时间的增加,管件拉伸强度逐步增大;随着熔体温度、注水压力的增大,管件拉伸强度逐步减小;工艺参数通过温度场的变化影响熔体的成核和晶体长大从而影响结晶度,结晶度越高,管件的拉伸强度越高。     

纳米蒙脱土对PA66/PP共混物结构与性能的影响!

通过融挤出制备了PA66/PP/纳米蒙脱土(OMMT)共混物,采用广角X射线衍射(WAXD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)等研究了OMMT在PA66/PP共混物中的分散及其对PA66/PP共混物力学性能、结构的影响。结果表明,OMMT主要为剥离状态分布于PA66/PP中。随OMMT含量增加,PP分散相尺寸逐渐减小,且5 phr OMMT时,PP分散相尺寸达到最小。PA66/PP/OMMT共混物的拉伸强度和模量呈上升趋势,缺口冲击强度下降。     

尼龙66/聚酚氧共混体系的共混形态和力学性能

采用扫描电镜、动态力学分析仪和材料试验机研究了尼龙66(PA66)与聚酚氧(PHE)共混体系的共混形态和力学性能。研究表明:氢键作用使得二者熔融共混后形成部分相容的两相聚集态结构;以PA66为主体时,PHE以颗粒形态分散在PA66基体中,随PHE含量增加,分散相颗粒尺寸下降;此时尼龙相的玻璃化转变温度(Tg)增大,PHE相的Tg提高,共混体系拉伸强度增加,冲击强度下降。PA66/PHE质量比达到40/60后发生相反转,PA66分散相颗粒尺寸明显小于PHE为分散时相的颗粒尺寸。PHE相的Tg随PA66含量增加而增大,随PA66含量增加,共混体系拉伸强度和冲击强度均增大。     

PVDF增韧PA6的结构及机理

采用聚偏氟乙烯(PVDF)对尼龙6(PA6)进行共混改性.通过采用不同的PVDF与PA6共混质量比例,研究了PA6/PVDF共混物的结构及性能.通过偏光显微镜和小角散射分析,发现PVDF的存在阻碍了PA6的结晶.通过拉伸试验发现,在PA6中加入PVDF使得PA6/PVDF共混物的拉伸强度、断裂伸长率和拉伸模量增加了.通过红外光谱分析发现,在拉伸前,PA6/PVDF共混物中只存在PVDF的α晶型,而拉伸后,α晶型消失了,与此同时出现PVDF的β晶型,由此得出,拉伸过程中PA6/PVDF共混物中PVDF分散相发生了由α晶型向β晶型的转变.     

PP/PA6/离聚物共混物的结构及力学性能

以乙烯-甲基丙烯酸钠盐离聚物(Surlyn8920)为添加剂,采用双螺杆共混和注塑法制备了聚丙烯(PP)/聚酰胺6(PA6)/Surlyn共混物,然后利用红外光谱测试仪、X射线衍射仪、差示扫描量热仪、扫描电子显微镜等对PP/PA6/Surlyn共混物的结构和力学性能进行了表征分析。结果表明,Surlyn与PA6发生络合作用,降低了PP与PA6两相的结晶温度、熔融温度、结晶度和结晶完善程度,使得分散相PA6的尺寸更小,分布更加均匀,明显改善了PP和PA6的界面相容性;当Surlyn的含量为7%(质量分数,下同)时增容效果较好,此时共混物的拉伸强度为40.59 MPa,断裂伸长率为156.3%,冲击强度为4.98 kJ/m~2。     

PA6/LDPE/PE-g-MAH共混纳米纤维的制备及结构研究

采用共混海岛纺丝法制备聚酰胺6/低密度聚乙烯/聚乙烯接枝马来酸酐(PA6/LDPE/PE-g-MAH)共混纤维,溶解剥离出LDPE基体相,可制备出PA6纳米纤维;研究了共混物的组成和纺丝条件对共混纤维的相结构、结晶、力学性能及PA6纳米纤维直径的影响。结果表明:随着共混物中PA6分散相含量增加,PA6纳米纤维的直径逐渐增大;PA6质量分数从30%增加至60%时,PA6纳米纤维平均直径由107 nm增至149nm;PA6质量分数为70%时,由于相逆转无法得到PA6纳米纤维;在PA6质量分数为55%条件下,提高拉伸倍数,PA6纳米纤维的直径进一步降低,且结晶度、力学性能增加。     

相容剂和加工工艺对PA1010/PP共混体系形态和力学性能的影响

以马来酸酐（MAH）和苯乙烯（St）多单体熔融接枝聚丙烯[PP-g-(MAH-co-St）]为相容剂,制备了聚酰胺10101/聚丙烯（PA1010/PP）共混体系。用毛细管流变仪、扫描电子显微镜、力学性能测试等方法研究了和加工工艺相容剂对PA1010/PP共混体系的形态和力学性能的影响。结果表明,相容剂PP-g-(MAH-co-St)有效降低了PA1010/PP共混体系的熔体流动速率;该共混体系熔体属于假塑性流体,熔体黏度随PP-g-(MAH-co-St)含量的增加逐渐增大;随着相容剂含量的增加,PA1010/PP共混体系中分散相PP的粒径逐步减小,力学性能得到改善,PA1010/PP/PP-g-(MAH-co-St)为70/25/5和70/20/10的共混体系的拉伸强度分别比PA1010/PP (70/30)共混体系提高了55.0 %和61.9 %,冲击强度分别提高了61.0 %和129.7 %;剪切速率为706.5 s-1时出现熔体破裂现象,剪切速率为5002.65 s-1时出现严重熔体破裂。     

PP-g-MAH增容PP/PA 6体系的分形理论分析

利用分形理论分析了聚丙烯(PP)与聚酰胺(PA) 6(质量比为80 : 20)增容共混体系.结果表明,马来酸酐接枝聚丙烯(PP-g-MAH)用量对体系分散相(PA 6)形状复杂程度的影响符合分形理论的无标度性(标度定律).在PP/PA 6增容共混体系中,分散相粒径在一定程度上随PP-g-MAH用量的增大而逐渐减小且形状趋于复杂化;分散相粒子分维数小于0.38时,提高分散相的形状复杂程度对提高材料力学性能有利.     

热处理对聚丙烯结晶结构和力学性能的影响

研究了不同热处理温度和热处理时间对聚丙烯(PP)结晶结构和力学性能的影响.结果表明:热处理对PP球晶分布、晶粒尺寸影响不大;退火处理使PP晶格参数略为下降;在90℃以上,随着热处理温度的提高,PP的结晶度不断增大;随热处理时间的延长,PP的结晶度先增大后趋于稳定;随热处理温度的提高和热处理时间的延长,PP拉伸强度提高,屈服强度增大,弹性模量增大,断裂伸长率和静力韧度下降,其变化规律与结晶度的变化相对应.     

PA6/载银沸石共混物结晶及流变性能的研究

将载银沸石与聚己内酰胺(PA6)进行共混,经熔融挤出制备PA6/载银沸石共混切片,并进行了结晶形态及流变性能分析.结果表明:PA6中载银沸石的引入产生了异相成核结晶,使PA6球晶变小,结晶度提高;PA6/载银沸石共混体系为假塑性流体,其表观粘度随剪切速率的增大而减小,随温度升高而降低,随着载银沸石含量的增加而减小;共混...     

Influences of component ratio of minor phases and charge sequence on the morphology and mechanical properties of PP/PS/PA6 ternary blends

In this study, influences of both component ratio of minor phases and charge sequence on the morphology and mechanical performance in typical ternary blends, polypropylene (PP)/polystyrene (PS)/polyamide-6 (PA6), have been studied. Reactive compatibilization of the blends has been carried out using multi-monomer melt grafted PP with anhydride groups and styrene segments. For uncompatibilized blends, scanning electron microscope (SEM) and selective solvent extraction showed that the blends presented a core–shell morphology with PS as shell and PA6 as core in the PP matrix, in spite of the component ratio and charge sequence. The shell thickened and droplet size decreased with increasing the PS/PA6 component ratio. While for compatibilized blends, the addition of compatibilizers resulted in a significant reduction of the dispersed droplet size and the phase structure of the dispersed phases was greatly dependent on the charge sequence. When the blending of PA6, g-PP, and PP are preceded, the encapsulation structure reversed into the structure of PS phase encapsulated by PA6 phase, which led to better tensile and flexural strength of the blends.     

水辅助注塑PP/EVOH共混物制品的相形态与阻渗性能

选择3种不同黏度的聚丙烯(PP)与聚乙烯醇(EVOH)共混制备质量比为90/10的共混物,并采用水辅助注塑(WAIM)将这3种共混物成型为中空制品。从WAIM制品靠近浇口(1^#)和末端(2^#)两个位置取出样品,通过扫描电镜观察样品壁厚上3个位置的相形态,并测试所取样品的甲苯渗透率。借助WAIM中高压水作用下模腔内熔体的流场对样品中3个位置的相形态进行了分析。对WAIM的高黏度比共混物制品2^#样品,在外表层和内表层分散相呈粗纤维状,芯层主要呈液滴状,其阻渗性能与相应的WAIM PP样品比有适度提高(约2.4倍);对WAIM的2种低黏度比共混物制品2^#样品,外表层和内表层分散相呈细纤维状,芯层呈粗长纤维状,其阻渗性能与相应的WAIM PP样品比提高幅度较大(其中对黏度比最小的共混物达9.8倍)。1^#位置所取3种WAIM PP/EVOH样品中分散相纤维的平均直径比2^#位置的大,导致1^#位置所取样品的阻渗性能比2^#位置的低。     

Blending PP with PA6 industrial wastes: Effect of the composition and the compatibilization

Blending polypropylene to recycled PA6 industrial wastes at different compositions, with and without compatibilizer PPgMA was produced in a corotating twin screw extruder where, polypropylene acts as the polymer matrix and polyamide as the dispersed phase. Several techniques were used to investigate the morphology, thermal, viscoelastic and tensile properties of these blend. Binary PP/PA6 blends showed the presence of PA6 particles dispersed in the PP continuous phase and exhibited a coarse morphology. Increasing PA6 contents in the blend increased their crystallinity and their size and improved the tensile properties at weak deformation. In addition to compatibilizer PPgMA, the morphology shows lower diameters and a decrease in size of the dispersed PA6 particles. The interfacial adhesion was also improved, as a result of the creation of an interphase that was formed by the interaction between the formed PPgPA6 copolymer in situ and both phases. This interphase induced an improvement in tensile properties. The PPgPA6 copolymer generated by the interphase was identified with DMA analysis thanks to an additional transition in loss modulus curves. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Compatibilization of polypropylene/nylon 6 blends with a polypropylene solid‐phase graft

The compatibilization of polypropylene (PP)/nylon 6 (PA6) blends with a new PP solid‐phase graft copolymer (gPP) was systematically studied. gPP improved the compatibility of PP/PA6 blends efficiently. Because of the reaction between the reactive groups of gPP and the NH₂ end groups of PA6, a PP‐g‐PA6 copolymer was formed as a compatibilizer in the vicinity of the interfaces during the melting extrusion of gPP and PA6. The tensile strength and impact strength of the compatibilized PP/PA6 blends obviously increased in comparison with those of the PP/PA6 mechanical blends, and the amount of gPP and the content of the third monomer during the preparation of gPP affected the mechanical properties of the compatibilized blends. Scanning electron microscopy and transmission electron microscopy indicated that the particle sizes of the dispersed phases of the compatibilized PP/PA6 blends became smaller and that the interfaces became more indistinct in comparison with the mechanical blends. The microcrystal size of PA6 and the crystallinity of the two components of the PP/PA6 blends decreased after compatibilization with gPP. The compatibilized PP/PA6 blends possessed higher pseudoplasticity, melt viscosity, and flow activation energy. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 420–427, 2004     

The effects of SEBS-g-maleic anhydride reaction on the morphology and properties of polypropylene/PA6/SEBS ternary blends

Ternary blends, based on 70% by weight of polypropylene (PP) with 30% by weight of a dispersed phase, consisting of 15% polyamide-6 (PA6) and 15% of a mixture comprising varying ratios of an unreactive poly[styrene-b-(ethylene-co-butylene)-b-styrene] (SEBS) triblock copolymer and a reactive maleic anhydride-grafted SEBS-g-MA, were produced via melt blending in a co-rotating twin-screw extruder. TEM revealed the blend containing only non-reactive SEBS to exhibit individual PA6 and SEBS dispersed phases. However, the progressive replacement of SEBS with reactive SEBS-g-MA increased the degree of interfacial reaction between the SEBS and PA6 phases, thus reducing interfacial tension and providing a driving force for encapsulation of the PA6 by the SEBS. Consequently, the dispersed-phase morphology was observed to transform from two separate phases to acorn-type composite particles, then to individual core-shell particles and finally to agglomerates of the core-shell particles. The resultant blends exhibited significant morphology-induced variations in both thermal and mechanical properties. DSC showed that blends in which the diameter of the PA6 particles was reduced to ≤3 μm by the increasing interfacial reaction exhibited fractionated PA6 crystallisation. In general, mechanical testing showed the blends to exhibit inferior low-strain tensile properties (modulus and yield stress) compared to the matrix PP, but superior ultimate tensile properties (stress and strain at break) and impact strength. These changes are discussed with reference to composite models.     

Fractionated crystallization of dispersed PA6 phase of PP/PP‐g‐MAH/PA6 blends

Fractionated crystallization behavior of dispersed PA6 phase in PP/PA6 blends compatibilized with PP‐g‐MAH was investigated by scanning electron microscopy (SEM), differential scanning calorimeter (DSC), polarized light microscopy (PLM), and wide‐angle X‐ray diffraction (WAXD) in this work. The lack of usual active heterogeneities in the dispersed droplet was the key factor for the fractionated crystallization of PA6. The crystals formed with less efficient nuclei might contain more defects in the crystal structures than those crystallized with the usual active nuclei. The lower the crystallization temperature, the lesser the perfection of the crystals and the lower crystallinity would be. The fractionated crystallization of PP droplets encapsulated by PA6 domains was also observed. The effect of existing PP‐g‐MAH‐g‐PA6 copolymer located at the interface on the fractionated crystallization could not be detected in this work. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3742–3755, 2004     

共混工艺对SMAH增容ABS/PA6共混物形态和力学性能的影响

以(苯乙烯/马来酸酐)共聚物(SMAH)为增容剂,研究了共混工艺对(丙烯腈/丁二烯/苯乙烯)共聚物/尼龙6(ABS/PA6)共混物聚集态结构和力学性能的影响。结果表明,ABS与PA6直接共混时相容性差;加入增容剂SMAH后,分散相尺寸变小且易均匀分散,显著改善了ABS/PA6共混物的力学性能。当ABS为连续相、PA6为分散相时,共混物的聚集态结构强烈地受共混工艺的影响,(ABS/SMAH)/PA6共混物的分散相尺寸最小、力学性能最优;当PA6为连续相、ABS为分散相时,共混物的聚集态结构基本不受共混工艺的影响。     

有机蒙脱土对PA6/PP合金体系的作用机制及其对材料性能的影响

研究了有机蒙脱土对PA6/PP合金体系的作用机制及其对材料性能的影响。结果表明,OMMT的添加可以提高体系的拉伸强度、弯曲强度和弯曲模量,但冲击强度会有某种程度的下降;OMMT主要分散在PA6连续相中,且当其添加量质量份数低于5%时,可以在PA6相中实现较充分的剥离;OMMT对PA6/PP合金体系有着显著的增容作用,这可能和片层对PP分散相凝聚时的阻隔,以及片层所起到的类似接枝物的增容作用有关;OMMT在PA6基体中被充分剥离后,将有利于使复合体系的拉伸强度、弯曲强度得到提高,但OMMT片层及和片层有关的类似接枝物的存在,将束缚并限制界面层附近PP相的屈服,而使材料冲击韧性下降。