硅烷交联聚乙烯及其纳米蒙脱土改性研究

【作者】 何庆龙；

【导师】 张广成；

【作者基本信息】 西北工业大学 ， 材料加工工程， 2003， 硕士

【摘要】 本文选择不同种类聚乙烯(PE)作为基体树脂，过氧化二异丙苯(DCP)作为引发剂，乙烯基三乙氧基硅烷(VTES)作为接枝单体，二月桂酸二丁基锡(DBTDL)作为催化剂，在双螺杆挤出机中进行了二步法硅烷交联聚乙烯的研究。讨论了PE种类、DCP和VTES含量以及交联温度、时间、螺杆转速等工艺条件对交联料的性能影响规律，研制出了综合性能优异的硅烷交联聚乙烯产品，并实际用于铝塑复合热水管中。 在此基础上，比较系统地研究了纳米蒙脱土(n-MMT)对硅烷交联聚乙烯的改性。探讨了母料法、直接共混法和溶液法三种n-MMT的分散方法，采用透射电子显微镜(TEM)、扫描电子显微镜(SEM)和X射线衍射(XRD)等手段表征了n-MMT在聚合物中的分散、插层状态，采用差示扫描量热法(DSC)研究了n-MMT对PE结晶行为的影响，研究了蒙脱土含量对硅烷接枝聚乙烯的性能影响。结果表明采用聚乙烯接枝马来酸酐(PE-g-MAH)作为载体树脂，先在双螺杆挤出机中制备纳米蒙脱土母料，再与硅烷接枝聚乙烯共混挤出制备硅烷接枝聚乙烯/蒙脱土纳米复合材料是一种可行的方法，能够实现PE分子链向蒙脱土的层间插层，并使接枝料的热稳定性、屈服强度、屈服模量提高，但使接枝料的断裂延伸率和交联料的交联度下降。当n-MMT含量为3～5％(质量百分比)之间，硅烷接枝聚乙烯/蒙脱土复合材料的综合性能较好。更多还原

【Abstract】 With dicumyl peroxide (DCP) as initiator, vinyl triethoxy silane (VTES) as monomer, dibutyl tin dilaurate (DBTDL) as catalyst, the thesis chooses different Polyethylene(PE) to study saline cross-linking of polyethylene(PEX) in the two-screw extruder. The effects of technics on the properties of PEX were studied, such as the kind of PE, the dosage of DCP and VTES, cross-linking reaction time and temperature, screw rotational speed. PEX has good performances and has been used to production of the aluminum-plastics compound pipe already.On the basis of above research, nano-montmorillonite (n-MMT) modified PEX was studied. Three dispersed methods was investigated, they are melt blending intercalation, mastbatch intercalation and solution intercalation. The structure of n-MMT in the polymer matrix was studied by means of TEM,SEM, XRD. The effect of n-MMT to crystallinity of PE by DSC and the content of n-MMT in matrix to the properties of PEX matrix was studied. The result showed that PEX/MMT nanocomposite was prepared through mastbatch intercalation is a feasible method and n-MMT can be intercalated by molecule chain of PE. This method use PE grafted MAH as carrier resin to prepare n-MMT mastbatch in the two-screw extruder. Mastbatch melt with PE grafted VTES and prepare PEX/MMT nanocomposite in the two-screw extruder. Compared with PEX, PE grafted VTES matrix has better yield strength, yield module, heat stability, and worse elongation rate, the gel fraction of PEX matrix decrease. When the content of n-MMT between 3 % to 5 %, PEX/MMT nanocomposite has better properties than PEX.更多还原