Photodegradation of polyethylene films formulated with a titanium‐based photosensitizer and titanium dioxide pigment

Abstract

SYNOPSISThis work reports on the photodegradation of low-density polyethylene films formulated with titanium (IV) oxide actylacetonate (TAc) and titanium dioxide pigment in different proportions; no previous reports on the photoactivity of this acetylacetonate have been found. Samples of blow-extruded films were submitted to accelerated UV aging with fluorescent lamps and the polymer degradation measured. The changes in carbonyl groups, molecular weight, and film elongation at break are discussed. The results show that TAc can promote photooxidation and accelerate the film degradation. The retention percent of elongation at break ( E B ) is apparently proportional to the carbonyl index irrespective of the formulation but has different relations with molecular weight ( M , ) , time, or the number of chain scissions ( n ) , probably as a result of microstructural differences.

Mn2Al-LDH- and Co2Al-LDH-stearate as photodegradants for LDPE film

“…those based on layered double hydroxides (LDH) are on the increase [30][31][32][33]. Nanoparticle incorporation into polymers has been explored for purposes of both photostabilization [34] and photodegradation [35]. Interestingly it was found that conventional smectite clay-based polyethylene nanocomposite showed enhanced susceptibility to photo-degradation [36].…”

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

“…It was considered that the reduction in tensile strength by photo degradation derived from the decrease in molecular weight and stress concentration [19]. In this and other studies [5,10,16], Mn and/or Mw of photo degraded PE increased compared to that of non-exposed samples in some cases. In addition, some studies [9,15] reported that high-molecular-weight molecules in molecular weight distribution curves of photo degraded PE increased compared to that of non-exposed samples in some cases.…”

“…), 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.…”

“…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.…”