In the present study, HDPE composites containing different concentrations of silver (Ag) nanoparticles (0.5%, 1%, 2%, 3%, and 5 wt%) were prepared by melt mixing on a Haake-Buchler Reomixer. Composites in the form of thin films were exposed to UV irradiation at 280 nm at constant temperature (25 °C) and relative humidity (50%) for several hours. The samples were characterized for their photochemical stability with several methods. From FTIR spectroscopy it was found that new chemical compounds were formed during UV exposure containing carbonyl, vinyl, and hydroxyl/hydroxyperoxide groups. According to the spectra, the nanoparticles act as inhibitors to the photo-oxidation mechanism of the polymer matrix. Moreover, as the loading of nanoparticles increased, better protection was achieved. Further study of the samples was performed using tensile strength tests, showing that neat HDPE was affected significantly by UV irradiation, while its composites with Ag were affected in a lower extend. The greater the loading of the nanoparticles in the polymer matrix, the more they reduce the mobility of the molecules, thus inhibiting the chain scission of HDPE. Degree of crystallinity was also affected from UV exposure time and the addition of nanoparticles. Finally, the mechanism of thermal degradation of HDPE and its composite with 1 wt% Ag before and after UV exposure was studied by Pyrolysis-gas chromatography–mass spectroscopy (Py-GC/MS).

在本研究中，通过在Haake-Buchler Reomixer上进行熔融混合，制备了包含不同浓度的银（Ag）纳米粒子（0.5％，1％，2％，3％和5 wt％）的HDPE复合材料。将薄膜形式的复合材料在恒定温度（25°C）和相对湿度（50％）下于280 nm的紫外线下照射几个小时。用几种方法对样品的光化学稳定性进行了表征。从FTIR光谱学中发现，在紫外线暴露期间形成了含有羰基，乙烯基和羟基/羟基过氧化物基团的新化合物。根据光谱，纳米颗粒充当聚合物基质的光氧化机理的抑制剂。而且，随着纳米颗粒的负载增加，获得了更好的保护。使用拉伸强度测试对样品进行了进一步的研究，结果表明，纯净的HDPE受紫外线辐射的影响显着，而其与银的复合材料受到的影响较小。纳米颗粒在聚合物基质中的负载越大，它们越减少分子的迁移率，从而抑制HDPE的断链。结晶度还受紫外线暴露时间和纳米颗粒添加的影响。最后，通过热解-气相色谱-质谱（Py-GC / MS）研究了HDPE及其含1 wt％Ag的复合材料在紫外线照射之前和之后的热降解机理。纳米颗粒在聚合物基质中的负载越大，它们越减少分子的迁移率，从而抑制HDPE的断链。结晶度还受紫外线暴露时间和纳米颗粒添加的影响。最后，通过热解-气相色谱-质谱（Py-GC / MS）研究了HDPE及其含1 wt％Ag的复合材料在紫外线照射之前和之后的热降解机理。纳米颗粒在聚合物基质中的负载越大，它们越减少分子的迁移率，从而抑制HDPE的断链。结晶度还受紫外线暴露时间和纳米颗粒添加的影响。最后，通过热解-气相色谱-质谱（Py-GC / MS）研究了HDPE及其含1 wt％Ag的复合材料在紫外线照射之前和之后的热降解机理。