Understanding the responses of materials to environmental variables is essential for performing meaningful accelerated weathering and service life prediction. Samples of polycarbonate-b-resorcinol polyarylate copolymer (RPA), poly(acrylonitrile-co-butadiene-co-styrene) (ABS), and two polycarbonate copolymers with silicone or aliphatic diacids were exposed in the NIST (National Institute of Standards and Technology) SPHERE (Simulated Photodegradation via High Energy Radiant Exposure) to determine the effects of ultraviolet intensity (UV irradiance), temperature, relative humidity (RH), and UV wavelength on yellowing and gloss loss and were compared to other aromatic polymers. All showed proportional response to irradiance (i.e., reciprocity) except ABS, which deviated notably at elevated temperatures. The activation energy for ABS yellowing was higher than other aromatic polymers (31 kJ mol⁻¹ ± 2 kJ mol⁻¹) while RPA had a slightly negative activation energy (-5 kJ mol⁻¹ ± 3 kJ mol⁻¹), reflecting differences in their photodegradation mechanisms. These two polymers also exhibited faster degradation when the RH was ≤ 10 % compared to ≥ 50 % RH. Wavelength effects varied among the polymers. The results indicate that predictive accelerated weathering should be performed with UV sources that accurately reproduce sunlight, at temperatures as close as possible to use conditions, and with RH > 10 %.

了解材料对环境变量的响应对于执行有意义的加速老化和使用寿命预测至关重要。聚碳酸酯的样品b -间苯二酚聚芳酯共聚物（RPA），聚（丙烯腈-共-丁二烯-共-苯乙烯（ABS）和两种含硅酮或脂族二酸的聚碳酸酯共聚物在NIST（美国国家标准技术研究院）SPHERE（通过高能辐射暴露进行的模拟光降解）中暴露，以确定紫外线强度（UV辐照度）的影响，温度，相对湿度（RH）和紫外线波长对泛黄和光泽损失的影响，并与其他芳族聚合物进行了比较。除ABS外，所有样品均显示出对辐照度（即互易性）的比例响应，而ABS在高温下显着偏离。ABS泛黄的活化能高于其他芳族聚合物（31 kJ mol ^-1 ±2 kJ mol ^-1），而RPA的活化能稍为负（-5 kJ mol ^-1 ±3 kJ mol ^-1）），反映出它们的光降解机理不同。当RH≤10％时，相对于≥50％RH，这两种聚合物还表现出更快的降解。波长效应在聚合物之间变化。结果表明，应使用可准确复制阳光的紫外线源，在尽可能接近使用条件的温度下，且相对湿度> 10％的情况下，进行可预测的加速风化。