摘要
系统研究了γ射线辐照改性聚丙烯(PP)的超临界二氧化碳(scCO_2)发泡行为。聚丙烯样品的制备采用两种辐照方法:(Ⅰ)PP粒子热压成型后γ射线辐照(Sequence Ⅰ,SⅠ);(Ⅱ)PP粒子γ射线辐照后热压成型(Sequence Ⅱ,SⅡ)。利用scCO_2作为物理发泡剂对两类样品进行间歇发泡。结果表明:γ射线辐照改性PP的熔点和结晶度随吸收剂量的增加而降低,其结晶度从51%下降到40%;在低频区,辐照后PP黏度轻微下降,而PP(SⅡ)样品下降更为明显;PP(SⅠ)发泡片材微孔尺寸变均匀,发泡率得到大幅提高,在40和50 kGy,不存在未发泡区域,并且拉伸性能从3.9 MPa增加到7.1 MPa;在最佳吸收剂量30 kGy时,发泡温度下降约5℃,发泡温度窗口从4℃增加到6~8℃。SⅠ方式可以降低发泡温度,扩大发泡温度窗口,更有利于PP的scCO_2发泡。
The effects of γ-ray irradiation on the supercritical carbon dioxide（scCO_2） foaming behavior of polypropylene（PP） were systematically studied. Sheets of PP were prepared through two different methods： irradiation after hot pressing（Sequence Ⅰ, SⅠ）, and hot pressing after irradiation（Sequence Ⅱ, SⅡ）. Carbon dioxide was used as the physical foaming agent. It was found that the crystallinities（51% to 40%） and melting points decreased with the increasing absorbed doses. At low frequency, the complex viscosity of PP decreased after irradiation, and the decrease was more pronounced for PP（SⅡ） than PP（SⅠ）. The PP（SⅠ） foam possessed an uniform cell size and a higher foaming rate, and its tensile strength increased from 3.9 MPa to 7.1 MPa compared with those of pure PP and PP（SⅡ）. In addition, at the optimum absorbed dose of 30 kGy, the suitable foaming temperature was around 145~153 ℃, and a wider foaming temperature（6~8 ℃） was obtained compared with the original 4 ℃. Therefore, irradiation after hot pressing（i.e., SⅠ） was considered more suitable for the foaming of irradiated PP, resulting in a higher tensile strength and a wider foaming temperature window.
作者
杨晨光
赵全
王谋华
邢哲
吴国忠
YANG Chenguang1,2 ZHAO Quan1 WANG Mouhua1 XING Zhe1 WU Guozhong1 1(Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Jiading Campus, Shanghai 201800, China） 2（University of China Academy of Sciences, Beijing 100049, China)
出处
《辐射研究与辐射工艺学报》
CAS
CSCD
2018年第1期22-30,共9页
Journal of Radiation Research and Radiation Processing
基金
国家自然科学基金(11079048)资助~~
