橋かけ高分子の化学レオロジー(第3報) : EPRへの応用

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The chemorheological treatments on vulcanized rubbers have already been studied, but these studies are founded on Tobolsky's theory, that is, the scission reaction occurs on one side of the polymer chain or on the crosslink site. The theory has hitherto been discussed, however, for both the extremities of scission reactions. That is of no practical use. An attempt is made in the present study to quantify the behavior having both the scission reactions of polymer chains and the crosslink sites by the stress-relaxation test. Now, each grade of scissions of polymer chains and crosslink sites are related as Eq. (1). k=Q_<ct>/(n_0/2)/(q_<mt>/M_0) (1) where, q_<mt> and Q_<et> are quantity of scission of polymer chains and crosslink sites, M_0 is monomer unit number and N_0 is initial crosslinking density. Accordingly, k means the grade of two scission mechanisms. Since, from Eq. (1). Q_t=q_<mt>+kN_0q_<mt>/(2M_0) (2) q_<mt>=2M_0/(k(N_<10>-N_<20>)){Q_<1t>-Q_<2t>} (3) Q_<1t> and Q_<2t> are total quantity of scissions for each samples which gives crosslinking density N_<10> and N_<20>. And the relaxation stress f_t/f_0 is related with total quantity of scissions Q_t as the following Eq. (4): f_t/(f_0)=(1-4kx/(k+2x)・Q_t/M_0)・e^<-2x^2/(k+2x)・Q_t/M_0>+2kx/(k+2x)・Q_t/M_0・e^<-4x^2/(k+2x)・Q_t/M_0> (4) where, x is degree of polymerization of network chains. Now, this theory is applied to EPR cured by peroxide. In this crosslinking structure, the bond structures at crosslink situations are all carbon-carbon chains. The bond distance on crosslink sites and polymer chains may vary, but negligibly so, and it is assumed that k of this samples will give 1.0. when k of identical value for these samples which give different x. EPR cured with peroxide satisfies the condition as k=1.0. Resulted q_<mt>-t curve is applied to EPR vulcanized with sulfur and peroxide. By replacement x=M_0/N_0 in Eq. (2). Q_t=(1+k/(2x))q_<mt> (5) Since this relates to Eq. (4), f_t/f_0-e^<-x/(M_0)・q_<mt>>=kq_mt/M_0{e^<-2x/(M_0)・q_mt>-2e^<-x/(M_0)・q_mt>} (6) This gives Y=kx. the resulting q_<mt> is substituted for the peroxide cured EPR in Eq. (6). In the result thus obtained k does not agree with 1.0. In this case the crosslink sites are of large probability for scission than polymer chains.
社団法人日本材料学会の論文
1967-07-15

橋かけ高分子の化学レオロジー(第3報) : EPRへの応用

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