<?xml version="1.0" encoding="utf-8"?><!DOCTYPE Zthes SYSTEM "http://zthes.z3950.org/xml/zthes-05.dtd">  <Zthes><term><termId>31370922</termId><termName>polyacrylonitrile</termName><termType>PT</termType><termNote><![CDATA[ A polymer made from the addition polymerization of acrylonitrile. Polyacrylonitrile was first made in the late 1930s and it quickly became an important type of synthetic rubber. ]]></termNote><termCreatedDate>2026-03-30 20:40:02</termCreatedDate><relation><relationType>BT</relationType><termId>31340150</termId><termName>thermoplastic</termName><termType>PT</termType></relation></term>  </Zthes>