稀土β成核剂对PP/OBC共混体系力学和结晶性能的影响

以均聚聚丙烯(PP)为原料,乙烯-辛烯嵌段共聚物(OBC)为增韧材料,稀土化合物(WBGⅡ)为β成核剂制备了PP/OBC共混体系,分析了WBGⅡ对PP/OBC共混体系结晶性能、晶型和晶体形态的影响,并测试了共混体系的力学性能。结果表明,随着OBC含量的增加,PP/OBC共混体系缺口冲击强度和断裂伸长率明显增大,拉伸强度和弯曲强度随之下降;含1.0%WBGⅡ母粒、15%OBC的PP/OBC共混体系,在152℃附近出现β晶型的特征熔融峰,结晶温度比纯PP提高了10.88℃,β晶型相对含量为21.94%,PP球晶尺寸减小,缺口冲击强度和断裂伸长率分别提高了264.82%和367.66%。     

振动注射对PP/HDPE共混物性能及晶型的影响

采用熔融共混法制备了聚丙烯(PP)/高密度聚乙烯(HDPE)共混物,研究了成型温度、振动频率、振动压力对共混物力学性能、结晶形态的影响。结果表明:高温下低频率振动,共混物的力学性能随振动压力的提高呈明显的上升趋势;WAXD测试结果表明:在一定振动条件下,共混物会有少量的次稳定晶型γ晶的生成。     

二苄叉山梨醇衍生物对PP/OBC共混材料的影响

以均聚聚丙烯(PP)为原料,乙烯-辛烯嵌段共聚物(OBC)为增韧材料,二苄叉山梨醇衍生物(YS-688)为成核剂,采用双螺杆挤出和注塑成型方法制备PP/OBC共混材料,用DSC、WAXD和POM分析了YS-688对PP/OBC共混材料结晶性能、晶型和晶体形态的影响,测试了共混材料的力学性能。结果表明:随着YS-688含量的增加,PP/OBC共混材料的缺口冲击强度呈先上升后下降趋势,拉伸强度和弯曲强度有所提高;含3.0%YS-688母粒的PP/OBC共混材料,与纯PP相比,熔融温度降低了2.32℃,结晶温度提高了12.30℃,α晶型的衍射峰强度增大,PP球晶尺寸减小,缺口冲击强度提高了204.23%,韧性较大幅度提高。     

芳酰胺类化合物对PP/OBC共混材料性能影响

以均聚聚丙烯(PP)为原料,乙烯-辛烯嵌段共聚物(OBC)为增韧材料,芳酰胺类化合物(TMB-5)为成核剂,采用双螺杆挤出和注塑成型方法制备PP/OBC共混材料,用DSC、WAXD和POM分析了TMB-5对PP/OBC共混材料结晶性能、晶型和晶体形态的影响,并测试了共混材料的力学性能。结果表明:随着OBC含量的增加,PP/OBC共混材料缺口冲击强度和断裂伸长率明显增大,拉伸强度和弯曲强度有所下降;含1.0%TMB-5母粒、15%OBC的PP/OBC共混材料,于152℃附近出现β晶型的特征熔融峰,熔融结晶温度比纯PP提高了11.68℃,β晶型相对含量为52.74%,PP球晶尺寸减小,缺口冲击强度和断裂伸长率分别提高了236.46%和256.01%,柔韧性大幅度提高。     

PTT/PP共混物的性能研究

通过熔融共混制备了聚对苯二甲酸丙二酯/聚丙烯(PTT/PP=75/25)及其马来酸酐接枝PP(PP-g-MAH)增容共混物,研究了PTT/PP及其增容共混物的结晶性能、力学性能、流变性能和结晶形态。研究结果表明,PTT与PP共混能提高PP、PTT组分的结晶温度;对于增容共混物,随PP-g-MAH用量的增加,PP和PTT的结晶温度基本不变。加入PP使PTT拉伸强度降低,冲击强度提高;PP-g-MAH增容使共混物的拉伸和冲击强度都提高。增容共混物的熔体粘度明显降低,存在明显的剪切变稀现象,但熔体粘度与PP-g-MAH用量无关。在一定用量范围内,随PP-g-MAH用量的增加,PP分散相的尺寸变小。     

XT-β晶型成核剂在PP中的应用

研究了XT-β晶型系列成核剂用于聚丙烯(PP)的改性,对试样的结晶性能、力学性能等进行了分析,评价了XT-β晶型成核剂的实际应用效果。结果表明：在PP中引入XT-β晶型成核剂后,试样的球晶尺寸明显减小,广角X射线衍射谱图出现了典型的口晶型特征衍射峰;试样的结晶速率、结晶温度明显提高,差示扫描量热法谱图出现a晶型、β晶型2个熔融峰,β晶型含量达到总结晶量的50％-80％;XT-β型成核剂可使体系保持较好的力学性能,PP负荷下热变形温度提高15～40℃。     

稀土β成核剂改性POM/EVA/PP三元共混材料的性能与表征

利用稀土β成核剂(WBGⅡ)对聚甲醛(POM)/乙烯—醋酸乙烯(EVA)/聚丙烯(PP)三元共混材料进行改性,借助PLM、WAXD、DMA等分析手段对该体系进行热力学分析及对体系的结晶行为、结晶形态进行了表征;并研究了其对共混体系力学性能的影响。结果显示:通过加入稀土β成核剂,POM/EVA/PP三元共混材料的相容性良好,且体系晶型发生明显变化,且加入少量稀土β成核剂,POM/EVA/PP三元共混材料的冲击性能及综合力学性能就可得到有效的改善。     

热处理对PP/PET共混体系结晶及力学性能的影响

研究了热处理对聚丙烯(PP)/聚对苯二甲酸乙二酯(PET)共混体系结晶、熔融行为及力学性能的影响。结果表明适当地对共混体系进行热处理,可有效改善材料的拉伸性能及弯曲性能,拉伸强度及弯曲强度最大增幅分别可达13%和33%。PP/PET共混体系力学性能的增加在于体系中聚合物结晶结构的完善、结晶度的提高以及热应力的消除,其中,PP的结晶度变化较大,由处理前的37.1%增加到处理后的52.1%。     

增容剂对PP/PA66共混物力学性能和结晶行为的影响

采用熔融共混法制备了聚丙烯(PP)/聚酰胺66(PA66)共混物,研究了聚丙烯接枝马来酸酐(PP-g-MAH)和乙烯-辛烯共聚物接枝马来酸酐(POE-g-MAH)作为增容剂对PP/PA66共混物力学性能和非等温结晶行为的影响。结果表明:PP-g-MAH提高了共混体系的拉伸强度,加入5份POE-g-MAH能显著提高共混物的断裂伸长率;PA66可起到异相成核作用,使PP的结晶峰温度升高;加入PP-g-MAH进一步提高了PP的结晶峰温度;PA66使PP的结晶活化能增大,增容剂的加入则使共混体系中PP的结晶活化能降低。     

原位聚合改性滑石粉/PP复合材料的微观结构和力学性能

通过熔融共混制备了丙烯酸丁酯(BA)原位聚合改性滑石粉/聚丙烯(PP)复合材料。研究了原位聚合改性对滑石粉/PP复合材料形貌、晶型结构、结晶熔融行为和力学性能的影响。结果表明,PP和滑石粉在熔融共混过程中,剪切力的作用使层叠的滑石粉剥离成不同厚度的片层,BA原位聚合改性改善了滑石粉与PP之间的界面粘结,有利于滑石粉在PP基体中的剥离;滑石粉的原位聚合改性,促进了β-晶型PP的生成,提高了滑石粉/PP复合材料中PP相的熔点、结晶速率和结晶度,降低了PP相的结晶温度。同时显著提高了滑石粉/PP复合材料的冲击强度,且存在一最佳的BA用量。     

Preparation and Properties of PB-1/PP Blends

Crystallization behavior, dynamic mechanical properties, mechanical properties and rheological properties of isotactic polybutene-1/polypropylene (PB-1/PP) blends prepared by melt-blending the two components through Brabender extruder were mainly studied via POM, DSC, DMA, capillary rheometer and so on, respectively. The results indicated that after adding PP in PB-1: size of the spherical crystal and degree of crystallization of PB-1 in the blends decreased, its melt temperature and crystallization temperature unchanged; tensile property of the blends was decreased, but impact and flexural properties were improved; change of the melt viscosity of the blends with the shear rate was more sensitive than pure PB-1.     

PB-1/BN导热复合材料的制备及性能研究

以聚丁烯-1(PB-1)为基体,二维片状氮化硼(BN)为导热填料,采用模压成型的方法制备了PB-1/BN导热复合材料。研究了BN用量对PB-1/BN导热复合材料导热性能、力学性能、流变性能以及结晶性能的影响。结果表明:BN的加入使复合材料的导热性能明显提高,当BN用量为50%时,复合材料的导热系数达到1.28 W/(m·K),与纯PB-1相比提高了266%;随着BN用量的增加,复合材料的力学性能明显下降;同时,其结晶温度和结晶度也有不同程度降低。     

可控流变PB-1的制备及PB-1/GF复合材料的性能表征

添加不同用量的过氧化物2,5二甲基2,5双(叔丁过氧基)己烷(DTBPH)制备熔体流动速率(MFR)不同的聚丁烯(PB-1),与玻璃纤维(GF)熔融共混制备PB-1/GF复合材料。通过对PB-1/GF复合材料表面形貌及力学性能的表征,探究了不同MFR的PB-1对GF的包覆效果。结果表明:低MFR的PB-1更能有效地包覆GF。材料的拉伸强度和弯曲强度随PB-1的MFR增加而大幅降低,而材料的冲击强度随PB-1的MFR增加变化不大。     

氢氧化铝含量对聚酯/玻璃纤维复合材料阻燃性能和力学性能的影响

通过熔融混炼和模压成型工艺,制备含氢氧化铝(ATH)的干式不饱和聚酯/玻璃纤维(UP/GF)共混复合材料。采用氧指数法(LOI)和垂直燃烧法(UL94)表征UP/GF复合材料的阻燃性能,采用DMA研究UP/GF复合材料的动态力学性能,采用静态力学方法研究UP/GF复合材料的冲击和弯曲性能。结果表明:UP复合材料中,ATH的含量在25%时,既能够满足V—0级阻燃级别,氧指数值为28.7%,且材料的冲击和弯曲强度分别为5.66kJ/m2和58.72MPa,同时也有较好的动态力学性能。     

Crystallization and dynamic mechanical properties of polypropylene/polystyrene blends modified with maleic anhydride and styrene

Polypropylene (PP)/polystyrene (PS) blends modified with reactive monomers, such as maleic anhydride (MAH) and styrene (St), and in situ formed PP/PS blends were prepared by melting extrusion. The crystallization and melting behavior and the dynamic mechanical properties of the PP/PS blends, including the structure of the grafted copolymer, were investigated with differential scanning calorimetry, dynamic mechanical analysis, and Fourier transform infrared. The results indicated that the addition of MAH hardly influenced the crystallization temperature of PP in the blends, but the addition of MAH and St increased the crystallization temperature of PP in its blends. The blends showed no remarkable variety for the melting temperature, but the shapes of the melting peaks were influenced by the addition of the reactive monomers. In addition, a significant increase in the storage and loss moduli of all the modified PP/PS blends was observed. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2038–2045, 2005     

Crystallization behavior of polybutene-1 in the anisotropic system blended with polypropylene

Development of supermolecular structure in drawn polypropylene (PP)/polybutene-1 (PB-1) blends was studied. PP (matrix)/PB-1 (70/30) blend films were drawn and heat-treated at fixed length or free ends at temperatures above the melting point of PB-1. It was found that a long axis of the PB-1 lamella is aligned perpendicular to the draw direction, and the c-axis of the PB-1 crystal is oriented perpendicular both to the draw direction and the plane of the surface of the blend film. Drawn, then heat-treated PP/PB-1 blend films gave a SAX pattern having a cross type scattering maximum on the meridian. It was confirmed that vertical scattering originates from the PB-1 crystal developed during melt recrystallization. It was proposed that the structural development of PB-1 in drawn PP/PB-1 film can be explained on the basis of transcrystallization of PB-1 in the confined 2-dimensional space in the PP matrix. The kinetics of isothermal crystallization of PB-1 was examined by use of a DSC technique. The result supports the conclusion that the heterogeneous nucleation of PB-1 followed by 2-dimensional crystal growth prevailed in oriented PP/PB-1 blend film.     

滑石粉对PB-1熔融、结晶行为的影响

采用双螺杆挤出机熔融制备了聚丁烯–1(PB-1)/滑石粉复合材料,研究了滑石粉含量对PB-1熔融及结晶行为的影响。结果表明,滑石粉显著促进了PB-1的结晶过程,其成核能力在滑石粉质量分数为1%时最佳。非等温结晶动力学研究表明,在滑石粉的实验用量范围内(1%～10%),要达到相同的结晶度,PB-1/滑石粉复合材料的完成温度明显高于纯PB-1的完成温度。当滑石粉质量分数为1%～5%时,要达到相同的结晶度,PB-1/滑石粉所需的时间明显比纯PB-1短;当用量为7%时稍短;当用量为10%时又稍长。但滑石粉不影响PB-1的依热成核方式和三维生长机制。偏光显微镜结果表明滑石粉对PB-1的异相成核作用显著。广角X射线衍射研究表明滑石粉阻碍了PB-1由晶型Ⅱ向晶型Ⅰ的转变过程,使晶型转变变缓。     

振动力场对聚丙烯/硅灰石复合材料性能的影响

采用三螺杆动态混炼挤出机通过熔融共混制备了聚丙烯(PP)/硅灰石复合材料,研究了振动工艺参数对材料力学性能及微观形态结构的影响。结果表明,PP/硅灰石复合材料的力学性能对振动参数的响应并不是单调增加,而是存在一个最佳的响应范围。在这一范围内,其综合力学性能得到极大提高。     

Recent Studies of Physical Properties of Highly Oriented Polyethylene

Recent studies of the structure and properties of ultra high modulus polyethylenes are presented. The physical properties received include dynamic mechanical behaviour, creep, shrinkage, shrinkage force, melting behaviour, thermal expansion and barrier properties.     

Studies on morphology,mechanical, thermal,and dynamic mechanical behavior of extrusion blended polypropylene and thermotropic liquid crystalline polymer in presence of compatibilizer

Polypropylene was melt blended in a single screw extruder with thermo tropic Vectra B‐950 liquid crystalline polymer (copolyester amide) in different proportions in presence of 2% of EAA, ethylene‐acrylic acid copolymer (based on PP) as a compatibilizer. The mechanical properties of such compatibilized blends were evaluated and compared in respect of their Young's Modulii, Ultimate tensile strength, percent elongation at break, and toughness to those of Pure PP. The Morphology was studied by using a polarizing light microscope (PLM) and Scanning electron microscope (SEM). The Thermal characterization of these blends were carried out by differential scanning calorimeter (DSC).The mechanical properties under dynamic conditions of such compatibilized blends and pure PP were studied by dynamic mechanical analyzer (DMA). Mechanical analysis (Tensile properties) of the compatibilized blends displayed improvements in Modulii and ultimate tensile strength (UTS) of PP matrix with the incorporation of 2–10% of LCP incorporation. The development of fine fibrillar morphology in the compatibilized PP/LCP blends had large influence on the mechanical properties. Differential scanning calorimeter (DSC) studies indicated no remarkable changes in the crystalline melting temperature of the blends with respect to that of pure PP. However, an increase in the softening range of the blends over that of PP was observed. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009