<?xml version="1.0" encoding="utf-8"?><!DOCTYPE Zthes SYSTEM "http://zthes.z3950.org/xml/zthes-05.dtd">  <Zthes><term><termId>31373509</termId><termName>perfluoropolyether</termName><termType>PT</termType><termNote><![CDATA[ A polymer featuring ether functionality, perfluoropolyether (PFPE) refers to one branch of a family of synthetic lubricants developed by DuPont, the oil form of the line commercially known as Krytox (TM). In a conservation context, it is used primarily for waterproofing stone. Its repellent powers also recommend it as an anti-graffiti agent. ]]></termNote><termCreatedDate>2026-03-30 20:40:43</termCreatedDate><relation><relationType>UF</relationType><termId>31373510</termId><termName>PFPE</termName><termType>ND</termType></relation><relation><relationType>UF</relationType><termId>31373511</termId><termName>perfluoropolyethers</termName><termType>ND</termType></relation><relation><relationType>BT</relationType><termId>31343235</termId><termName>polymers</termName><termType>PT</termType></relation></term>  </Zthes>