ABSTRACT

Rigid, unplasticized poly(vinyl chloride) (PVC-U) sheet products were evaluated comprehensively for the first time with regard to their use in museum showcase construction. The compositions of numerous name brand products (Sintra, Forex, Komatex, Komacel, Celtec, Ex-cel FF, PALIGHT, and ePVC) have been determined using pyrolysis-gas chromatography-mass spectrometry, while their volatile emissions were assessed using modified Oddy tests as well as direct thermal desorption chromatography at elevated temperatures. Despite frequently passing the aggressive conditions of the Oddy test, most premium quality brands were found to release 2-ethylhexyl thioglycolate (2-EHTG), a sulfur-bearing byproduct of a heat stabilizing additive. Importantly, only the economy versions of PVC-U analyzed in this study (Komacel and ePVC) did not contain the sulfur compound. This volatile thioglycolate was shown here using molecular spectroscopies to deposit on and react with copper and silver surfaces. Similarly, lead white pigmented watercolor was blackened by the thioglycolate. Based on these results, alternative materials are recommended for display cases that will contain sulfide-sensitive materials like metals.

摘要

首次对刚性、未增塑的聚氯乙烯 (PVC-U) 板材产品在博物馆展示建设中的应用进行了全面评估。许多名牌产品（Sintra、Forex、Komatex、Komacel、Celtec、Ex-cel FF、PALIGHT 和 ePVC）的成分已使用热解-气相色谱-质谱法测定，而其挥发性排放物则使用改进的 Oddy 测试进行评估以及高温下的直接热解吸色谱法。尽管经常通过 Oddy 测试的苛刻条件，但发现大多数优质品牌都会释放 2-乙基己基巯基乙酸盐 (2-EHTG)，这是一种热稳定添加剂的含硫副产品。重要的，只有本研究中分析的经济型 PVC-U（Komacel 和 ePVC）不含硫化合物。这种挥发性巯基乙酸盐在此使用分子光谱学显示在铜和银表面上沉积并与之反应。同样，铅白颜料水彩画被巯基乙酸盐变黑。基于这些结果，建议将替代材料用于包含金属等硫化物敏感材料的展示柜。