【作者】 汪永斌；

【导师】 张丽叶；

【作者基本信息】 北京化工大学 ， 材料学， 2006， 硕士

【摘要】 长支链型高熔体强度聚丙烯（LCB-HMSPP）是一种具备较好熔体弹性，较高熔体强度、微凝胶含量的PP树脂，LCB-HMSPP克服了均聚线性PP应变软化的缺陷，具有应变硬化的拉伸流变特性，可在较宽的温度范围内稳定地表现出较高的熔体强度，有利于挤出发泡等加工工艺。 本文在线性PP中加入1，4-丁二醇二丙烯酸酯（BDDA），经小剂量⁶⁰C_o-γ高能辐照，制备了LCB-HMSPP。采用ARES高级流变扩展系统和毛细管流变仪研究了该LCB-HMSPP的剪切流变行为，采用熔垂仪研究了LCB-HMSPP的抗熔垂能力，采用Rheotens拉伸流变仪研究了LCB-HMSPP的拉伸流变行为。讨论了敏化剂含量、辐照剂量、添加高分子量物质对PP熔体粘弹性、离模膨胀比、抗熔垂能力、剪切和拉伸流变行为的影响，提出了PP辐照过程中长支链的形成机理。 研究发现，辐照制备的LCB-HMSPP熔体弹性显著增强，表现在其低频端储能模量G’提高，内耗正切tanδ变小，零切粘度η₀增大，特征松弛时间τ₀变长。LCB-HMSPP的离模膨胀比增大，熔体流动速率降低，凝胶含量较低，具备较好的流动性。辐照改性后，LCB-HMSPP的抗熔垂能力、熔体强度和拉伸粘度显著提高，具有“应变硬化”的拉伸流变特性。 LCB-HMSPP的熔体弹性、离模膨胀比、抗熔垂能力和拉伸粘度、熔更多还原

【Abstract】 This paper dear with the preparation, rheological properties, as well as extrusion foaming of high-melt-strength polypropylene with long chain branching structure (LCB-HMSPP). LCB-HMSPP was achieved by 60Co-γ ray irradiation in presence of bi-functional monomer. ARES (advanced rheology expended system), capillary rheometer and Gottfert rheotens extensional rheometer were introduced to investigate the shear and extensional rheological behavior of this LCB-HMSPP. In addition, sag resistance, another important parameter to characterize melt strength, was also carried out. Effect of sentilizer content, radiation dose and adding a small amount of high molecular weight component on shear and extensional rheological behavior, such as melt elasticity, die swell, melt flow rate, sag resistance, melt strength and transient extensional viscosity, were intensively discussed. Meanwhile, mechanism of forming the long chain branching structure of PP during high energy irradiation was proposed.As evidenced by ARES, capillary rheometer, sag resistance and rheotens更多还原