英语翻译We need polymers that have a controlled average molecular weight and a molecular weight distribution.Thus,the polymerization reactions must have an “off” switch as well!The chains may be terminated by two mechanisms.First the ends of
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英语翻译We need polymers that have a controlled average molecular weight and a molecular weight distribution.Thus,the polymerization reactions must have an “off” switch as well!The chains may be terminated by two mechanisms.First the ends of
英语翻译
We need polymers that have a controlled average molecular weight and a molecular weight distribution.Thus,the polymerization reactions must have an “off” switch as well!The chains may be terminated by two mechanisms.First the ends of two growing chains may be joined.This process,called combination,creates a single large chain from two smaller chains.Second,the active end of one chain may remove a hydrogen atom from a second chain by a process known as disproportionation.This reaction terminates two chains,rather than combining two chains into one larger chain.Sometimes,compounds known as terminators are added to end the polymerization reactions.In general,for thermoplastics,the higher then average molecular weight the higher will be the melting temperature and the higher will be the Younger’s modulus of the polymer.The following example illustrates an addition polymerization reaction.
英语翻译We need polymers that have a controlled average molecular weight and a molecular weight distribution.Thus,the polymerization reactions must have an “off” switch as well!The chains may be terminated by two mechanisms.First the ends of
我们需要的是平均分子量受控制的和分子量分配的聚合物.因此,聚合反应必须要有一个“关闭”的开关.这个锁链应由两台机械终结.首先,两个发展中的锁链的末端将结合在一起.这个过程称为化合,有两个小的链条形成一个巨大的链条.其次,通过自身氧化还原过程,一条链的活跃端从第二条链移去一个氢原子.这个反应毁掉两条链的几率比结合两条链更大.有时,化合物被当做终止剂加入聚合反应中,以停止其反应.通常对于热塑性塑料来说:平均分子量越大,其熔点越高,聚合物的杨氏系数也就越高.以下的例子阐述了一个加成聚合反应.