PP／EPO和LDPE／EPO共混体系的相容性、结晶结构、结晶动力学的研究

用WAXD、TBA、DSC等方法对PP／EPO共混体系的结晶结构和相容性进行了研究。WAXD方法测定表明PP／EPO共混体系的结晶度随EPO组份含量的增加而降低，晶胞参数值与组份比无关，使用Hosemann次晶模型法计算了此体系的第二类晶格畸变和应力畸变，表明衍射峰的宽化主要是由第二类晶格畸变引起的。根据DSC和TBA实验得出在所有组成PP／EPO共混体系是不相容的，但在非晶区可能部分相容。采用WAXD、DDV、DSC等方法对LDPE／EPO共混体系的结晶结构和相容性进行了研究，用Ruland方法计算的结晶度值随EPO组份含量的增加而降低，晶胞参数值与组份比无关。使用方差——范围函数方法计算了LDPE／EPO共混体系的（110）和（200）晶面的微晶大小（L_(hkL))和晶格畸变参数（g_t）。L_(hkL)和g_t值随EPO组份的增加而下降。从DDV－II粘弹谱仪测得的共混体系的谱图可看出，在β松驰附近，EPO的β转变随LDPE的加入量增加向低温方向移动，这是由于渗透到EPO非晶中的LDPE非晶部分影响了EPO链段运动所致。从LDPE／EPO共混体系的DSC图谱可知，只存在一个熔融峰，这说明很可能LDPE与EPO形成了共晶，从共混物的Tm、Tc可知，随EPO组份增加，熔点下降，结晶温度下降，纯EPO显示出高于LDPE及共混物的Tm.WAXD法证明，这是由于EPO中PE长序列贡献的结果。为了进一步证实EPO中少量结晶相与LDPE中晶相形成了共晶，我们做了萃取实验，结果表明了共晶的存在。由于各种聚乙烯的非晶相间是任意混容的，大部分为非晶部分的EPO中少量结晶相又与LDPE的结晶相形成了共晶，因盯LDPE／EPO是相容的共混体系。用DSC方法研究了LDPE／EPO共混体系的结晶动力学，对LDPE／EPO共混体系的等温结晶动力学研究表明，共混物是三维生长的异相成核。共混体系的平衡熔点随EPO含量的增加而降低，采用Lauritzen提出的Z判断方法，得出共混体系在各个结晶温度下的结晶过程都是以方式（II）进行的。采用Avrami方程和Ozawa方程的新的处理非等温结晶动力学的方程，研究了LDPE／EPO共混体系的非等温结晶动力学，得到了描述非等温结晶过程的一些基本参数。

LDPE/EPM/炭黑导电复合材料的研究

制备了低密度聚乙烯 (LDPE) /二元乙丙橡胶 (EPM) /炭黑导电复合材料。用带功能基团的表面改性剂对炭黑进行表面处理 ,在炭黑低填充量下即获得了导电率高、综合性能优良的导电复合材料。研究了基体树脂的结构、工艺方法、炭黑的预处理、复合材料的后处理 (退火 )等对LDPE/EPM/炭黑导电复合材料导电性能的影响。

LDPE/carbon black conductive composites: Influence of radiation crosslinking on PTC and NTC properties

The electrical resistivity of low-density polyethylene/carbon black composites irradiated by Co-60 gamma-rays was investigated as a function of temperature. The experimental results obtained by scanning electron microscopy, solvent extraction techniques, and pressure-specific volume-temperature analysis techniques showed that the positive temperature coefficient (PTC) and negative temperature coefficient (NTC) effects of the composites were influenced by the irradiation dose, network forming (gel), and soluble fractions (Sol). The NTC effect was effectively eliminated when the radiation dose reached 400 kGy. The results showed that the elimination of the NTC effect was related to the difference in the thermal expansion of the gel and Sol regions. The thermal expansion of the sol played an important role in both increasing the PTC intensity and decreasing the NTC intensity at 400 kGy.

辐射效应对LDPE/CB复合物电性能的影响

研究了γ射线辐照交联后的低密度聚乙烯 (LDPE) /碳黑 (CB)复合物在不同温度下的导电性能。应用扫描电子显微镜研究了不同剂量对复合体系正温度系数 (PTC)效应以及负温度系数(NTC)效应的影响。结果表明 ,辐射剂量对PTC和NTC效应的影响很大。在 4 0 0kGy时 ,NTC效应基本消除 ,当辐射剂量继续增加时 ,NTC效应又重新出现。

Deformation process and mechanism of HDPE/LDPE blends

Blends of HDPE in more LDPE, with appropriate heat treatment, produce a dispersion of separate entities of HDPE in a matrix of LDPE. The system offered an especially favourable means of studying the deformation of melt-crystallized lamellae. It has been found that sheaf-like spherulites are transformed under tensile deformation into hourglass shapes i.e. a double cone aligned along the drawing direction with origin in the center of the object. This is a consequence of different modes of deformation according to the relation of an individual lamella to the tensile axis. The work shows that the lamellae have not undergone melting and recrystallization in the deformation process at room temperature.

HDPE/LDPE共混物形变过程中的结构变化及机理

聚合物熔体结晶由于链缠结等因素的影响，其形态结构非常复杂，这给研究结晶聚合物的微观结构，特别是聚合物在拉伸过程中的形态变化带来很大困难．本文将高密度聚乙烯（ＨＤＰＥ）和低密度聚乙烯（ＬＤＰＥ）两种不相容的组分进行共混，使少量ＨＤＰＥ分散在ＬＤＰＥ中，…

LLDPE及VLDPE对LDPE\HDPE共混物拉伸性能的影响

研究了线性低密度聚乙烯（ＬＬＤＰＥ）和极低密度聚乙烯（ＶＬＤＰＥ）对高密度聚乙烯（ＨＤＰＥ）＼低密度聚乙烯（ＬＤＰＥ）共混物拉伸性能的影响。由于ＬＬＤＰＥ或ＶＬＤＰＥ的加入，改善了ＨＤＰＥ与ＬＤＰＥ间的相互作用，提高了ＨＤＰＥ＼ＬＤＰＥ共混物的拉伸性能。

PPA在LLDPE/LDPE农膜加工中的应用

本工作以LLDPE／LDPE为基料，添加氟弹性体加工改性剂DynamarPPA，采用LDPE挤出机加工农膜。结果表明，挤出机加工LLDPE的能力大幅度地提高，使共混物中LLDPE含量从原来的40％增加到80％，薄膜的物理机械性质亦有明显改善，而主机电流和挤出量未见变化。在添加无滴剂母料条件下，可加工LLDPE总含量达95％的无滴膜，且该膜的力学性质和光学性质均住。

辐射增强 PP/LDPE 共混体系力学性能的研究

研究了在多官能团单体—三烯丙基异腈脲酸酯存在下，ＰＰ／ＬＤＰＥ共混物的辐射效应，并用ＳＥＭ、ＤＳＣ和动态力学性能对其形态结构和相容性进行了表征。结果表明：通过添加三烯丙基异腈脲酸酯，用辐射可以强化ＰＰ／ＬＤＰＥ共混物的相间结合力，改善共混物的相容性，从而提高共混物的力学性能。

PP/LDPE共混体系的辐射效应

研究了在多官能团单体—三烯丙基异氰脲酸酯存在下ＰＰ／ＬＤＰＥ共混体系接受γ－辐射的效果。用溶解度参数和ＴＥＭ技术评估了共混体系的相容性与多官能团单体在共混体系中的分布，并用ＳＥＭ、ＤＳＣ、动态力学等方法对共混体系相容性进行了表征。结果表明，ＰＰ／ＬＤＰＥ是不相容的共混体系，三烯丙基异氰脲酸酯主要分布在共混体系的相界面区域，辐照强化了共混体系的相间结合，增加了界面厚度，改善了共混体系的相容性。

LLDPE/LDPE薄膜加工改性剂PPA

以LLDPE/LDPE共混树脂为基料,添加加工改性剂氟弹性体PPA,采用挤出吹塑成型加工薄膜制品。以LLDPE/LDPE质量比为1/2作空白样。按每克试样总量中含500μg PPA的比例添加PPA,当共混物中LLDPE含量为1/3时,挤出机电流下降,薄膜的透光率增加,雾度降低;LLDPE含量为60％时,挤出机电流未变而产量提高,薄膜的透光率和雾度变化不大;继续增加LLDPE比例时,挤出机电流和雾度增加。薄膜的拉伸性能随LLDPE比例增大显著提高,且纵横向的取向度变小。

LLDPE／LDPE共混体系的相容性与性能

ＬＬＤＰＥ／ＬＤＰＥ共混体系的相容性与性能杨毓华，花荣，白春霞，于旻李三喜，葛铁军（中国科学院长春应用化学研究所长春１３００２２）（沈阳化工学院高分子系沈阳）关键词ＤＳＣ，ＷＡＸＤ，力学性能，ＬＬＤＰＥ，ＬＤＰＥ，共混，相容性非晶－非晶－结晶共混体系...

EFFECT OF GAMMA-RADIATION ON DYNAMIC VISCOELASTIC PROPERTIES AND THERMAL-BEHAVIOR FOR LDPE

The effect of gamma-radiation on dynamic viscoelastic properties and thermal behavior for low density polyethylene(LDPE) have been investigated. The store energy modulus (E) of the samples increased after radiation. The beta and alpha transition temperature shifted to higher temperature with increasing irradiation dose. The results of thermal analysis show that crystal melting temperature (Tm), enthalpy(DELTAHm) and crystal disapperance temperature(Td) for irradiated samples decreases with increasing of dose.

THE EFFECT OF RADIATION-INDUCED CROSS-LINKING ON THE RELAXATION OF TAUT TIE MOLECULES DURING ANNEALING OF DRAWN LDPE

Shrinkage, retractive stress, and infrared dichroism of the drawn low-density polyethylene (LDPE) as-drawn and irradiated by Co-60-ray have been measured under different annealing conditions. The shrinkage and the disorientation of the irradiated sample was undergone more rapidly than that of unirradiated one as the temperature was continuously increased, surpassing a certain value, and a higher degree of shrinkage and disorientation was achieved finally for the irradiated sample when the samples were annealed with free ends. For the samples heated isothermally with fixed ends, the retractive stress went through a maximum and then attenuated to a limited value, and the degree of such a stress attenuation for the unirradiated sample was much more than that for the irradiated sample. These results show that the taut tie molecules (TTMs) in drawn PE can relax by the pulling of chain segments out of crystal blocks that they anchored in at elevated temperatures higher than the a transition and also by the displacing of microfibrils if the samples were annealed with free ends. The cross-links produced by irradiation prohibit the former process. It was further observed that the dependence of the average extinction coefficient of the band at 2016 cm-1 on that of the band at 1894 cm-1 is related to irradiation and annealing conditions, which has also been explained by the relaxation of TTMs and the function of irradiation-induced cross-linking on the relaxation.

LDPE/EVA共混体系的结晶行为

本文通过DSC、WAXD、偏光显微镜、DMA等方法,对LDPE/EVA共混体系进行了研究。结果表明,EVA可使LDPE的熔融峰温提高15℃。并在LDPE结晶过程中起稀释剂作用。LDPE/EVA共混体系为非晶相相容。