A polythioether comprising: R.sup.4 --S.brket open-st.R.sup.1 --S--CH.sub.2 CH.sub.2 --(R.sup.2).sub.m --S.brket close-st..sub.n R.sup.1 SR.sup.4 wherein R.sup.1 is a C.sub.1-10 alkyl, --(R.sup.3 Q).sub.p R.sup.3 -- or C.sub.6 -C.sub.20 aryl where Q is O or S, each R.sup.3 is independently C.sub.1-6 alkyl, and p is an integer between 0 and 6; R.sup.2 is C.sub.1-6 alkyloxy or C.sub.5-12 cycloalkyloxy, R.sup.4 is H, C.sub.1-6 alkyl, C.sub.1-6 alkyl alcohol and C.sub.0-6 alkyl substituted with .brket open-st.CH.sup.2 CH.sub.2 (R.sup.2).sub.m.brket close-st.X, where X is a halogen, m is an integer between 1 and 4, and n is an integer selected to yield a molecular weight for said polythioether of between 1000 and 10,000 Daltons.