Characterization of photo-oxidative degradation process of polyolefins containing oxo-biodegradable additives

• Published in: Polymer (Guilford) 2022-12, Vol.262, p.125455, Article 125455
• Main Authors: Padermshoke, Adchara, Kajiwara, Tomoko, An, Yingjun, Takigawa, Mamiko, Van Nguyen, Toan, Masunaga, Hiroyasu, Kobayashi, Yutaka, Ito, Hiroshi, Sasaki, Sono, Takahara, Atsushi
• Format: Article
• Language: English
• Subjects: Carbonyl index; Oxo-biodegradable additives; Photo-oxidative degradation; Polyolefins
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/j.polymer.2022.125455

The effects of oxo-biodegradable additives on the photo-oxidation of four types of polyolefin polymers, namely high-density polyethylene (HDPE), low-density PE (LDPE), linear low-density PE (LLDPE), and isotactic polypropylene (itPP) were investigated. Scanning electron microscopy, infrared spectroscopy, differential scanning calorimetry, and wide- and small-angle X-ray scattering were employed to gain insights into the chemical and structural modifications induced by the degradation process. The photo-oxidation preferentially occurred at the sample surface and was favored in the amorphous region of the polymers. The carbonyl index calculated for the neat and additive-containing samples suggested that the additives promoted the photo-oxidative degradation, particularly of the PE polymers, which are intrinsically resistant to oxidation, without altering their degradation pathways. The overall degradation rate of the additive-containing polymers was in the order of itPP > LDPE > LLDPE > HDPE. [Display omitted] •Oxo-biodegradable additives promoted oxidative degradation during UV irradiation in air.•Photo oxidative degradation preferentially occurred at surface and amorphous region.•Photo oxidative degradation rate was in the order of itPP > LDPE = LLDPE > HDPE.