Study of polyethylene photodegradation in formulations with a system of interacting photostabilizers and antioxidants

Abstract

SYNOPSISThe accelerated UV photodegradation process of low-density polyethylene films, formulated with two photostabilizers and two antioxidants, was studied to evaluate the effect of different combinations of UV stabilizers and antioxidants on the overall photodegradation process. An experimental design, consisting of 33 formulations with different additive ratios and a blank, was used to evaluate the performance of the four mixed additives. From each formulation, 200 micron-thick films were produced by the extrusion-blowing process. Samples from these films were submitted to accelerated UV aging, and the polymer degradation was measured by carbonyl group evolution, molecular weight distribution changes, and maximum elongation loss. The effect of the additive combination on the different degradation reactions is discussed qualitatively by using "relative variables" and a triangular diagram. 0 1996

New Indoor Accelerated Weathering Condition for Approximating Molecular Weight Distribution of Outdoor-Exposed LDPE

“…At the same time, the correlation coefficient adjusted for the degrees of freedom in multiple regression analysis using both Mn and Mw did not increase from single regression analysis using Mn only as an explanatory variable. From the data of Berlang-Duarte et al [11] (except commercial film), Mw had the highest correlation coefficient with elongation in single regression analysis (R = 0.73). At the same time, the correlation coefficient from multiple regression analysis using both Mn and Mw did not increase from single regression analysis using Mw only as an explanatory variable.…”

“…), hydroxyl group and peroxy group, vinyl group, etc. occur during photo degradation of polyolefin [5][6][7][8][9][10][11][12][13][14][15].…”

“…For analyzing the relationship between molecular weight and physical properties, the authors conducted single regression and multiple regression analyses using the data described in previous studies [10,11]. The authors used molecular weights as explanatory variables and physical properties as target variables.…”

“…The previous studies [10,11] contain the data of Mn, Mw, and elongation. From the data of Angulo-Sanchez et al [10], Mn had the highest correlation coefficient with elongation in single regression analysis (R = 0.89).…”

“…Therefore, a new accelerated weathering occur in photo-oxidation not in thermo-oxidation [3,4]. The photo degradation mechanism of polyolefin degraded due to outdoor exposure or accelerated weathering testing has been investigated in detail, and the photochemical reaction mechanism [5][6][7][8][9][10][11][12][13][14], IR (infrared) spectroscopy spectrum behavior [5,[8][9][10][11][12][13][14][15], and molecular weight and molecular weight distribution behavior [5,[9][10][11]15] of photo degraded polyolefin have been reported.…”