摘要
研究和探讨了聚合物结构和运动的多重性以及对其辐射交联机制和规律性的影响,并对Charlesby-Pinner方程及其不同修正式的适用性进行讨论。通过广角X射线衍射(WAXD)、差示扫描热法(DSC)、电子顺磁共振(ESR)等技术及凝胶和溶胶分析方法,对聚酰胺(PA)、聚氧化乙烯(PEO)、聚乙烯(PE)等不同聚合物的辐照效应与其结构关系进行了研究,对相关文献提供的结果做了详细讨论。在辐照初始低剂量区,由于端基效应(端联)和主链交联导致交联按非无规交联机制进行(交联度q0(D)=q0AXA+q0BXB是剂量的函数),是导致聚合物辐射交联溶胶分数(s)与剂量(D)实验数据偏离Charlesby-Pinner经典无规交联关系的主要原因,当端基随剂量增大消耗至端基效应可以忽略时,聚合物非晶区主链单元的交联符合Charlesby-Pinner方程辐射无规交联机制假定,实验与理论一致(结晶相不参与反应);;当剂量继续增大,因结晶表面(中间相)介入交联过程,反应又按非无规方式进行。
In an attempt to explore the effects of structure and mobility multiplicity of polymers on the mecha- nism of radiation crosslinking, the adaptability of Charlesby-Pinner’s equation and its various modified versions are examined. In the present paper, the effects of chain structure and state of aggregation on radiation crosslinking of polyethylene, polyethylene oxide and polyamides were studied with emphasis on the roles played by end groups, chain branches, and morphological factors. The experimental data of other polymers reported in the literature are also gathered and carefully analyzed. It is indicated that both chemical and morphological multiplicity of polymer struc- ture result in the multiplicity of crosslinking mechanism, and which it is main reason of deviation between experi- mental date and those predicted by the Chharlesby-Pinner’s equation. The deviation at lower doses is closely asso- ciated with the structure and content of end groups of the polymer. In this stage, radiation crosslinking reaction takes place non-randomly. With the increase in radiation dose and the gradual consumption of end groups, the effect of end groups tends to become ignorable. Then the crosslinking reaction proceeds randomly, and the experimental date on this stage conform to the Chalesby-Pinner equation perfectly. Random crosslinking of main chain units is the characteristic reaction of amorphous phase only. When the radiation dose further increases, crosslinking takes place nonrandomly, since the Crosslinking reaction in interface of crystalline and amorphous phases.
出处
《辐射研究与辐射工艺学报》
CAS
CSCD
北大核心
2004年第3期129-138,共10页
Journal of Radiation Research and Radiation Processing
基金
国家自然科学基金(82020089
86020305)资助
关键词
聚合物
辐射交联机理
结构和运动多重性
辐射效应
Radiation effects, Radiation crosslinking mechanism, Structure, Mobility of polymer
