Influence of UV stabilizers on the weathering of PETG and PCTT films

Abstract

The influence of two UV photostabilizers on the photostability of Polyethylene-co-CHDM-terephthalate (PETG) and Polycyclohexylenedimethylene-Co-TMCD-terephthalate (PCTT) copolyester films was investigated. Untreated films and films containing stabilizer were irradiated. The resulting films were analyzed by attenuated total reflectance Fourier transform infrared (ATR FTIR) spectroscopy, gel permeation chromatography (GPC), and X-ray photoelectron spectroscopy (XPS). FTIR spectra of the irradiated films containing Cyasorb 1164 showed less change in intensity of the broad peak corresponding to OH groups, than the films containing Cyasorb 3638, indicating that Cyasorb 1164 is a better photostabilizer for these films. XPS results showed that the decrease in C/O ratio, due to photodegradation, was greater in films containing Cyasorb 3638 compared to those containing Cyasorb 1164. The formation of degradation products was evident from emission spectra arising from extracts of irradiated films based on PCTT +10% Cyasorb 3638, but no degradation products were apparent in extracts from irradiated PCTT +10% Cyasorb 1164. UV-absorption spectra of Cyasorb 1164 overlap more substantially with the absorption spectra of PETG and PCTT. The results from FTIR, XPS, and GPC analyses of the irradiated PETG and PCTT films demonstrated that Cyasorb 1164 was more effective than Cyasorb 3638 in enhancing resistance to UV-induced weathering.

Terephthalic Acid Copolyesters Containing Tetramethylcyclobutanediol for High‐Performance Plastics

“…[32] A commercial Tritan (TPA‐TMCD/CHDM) polymer had 53.1 kDa M w and 26.5 kDa M n [16] and a TMCD modified PCT (PCTT) (TPA‐CHDM/TMCD) film had 64.5 kDa M w and 28.9 kDa M n from GPC based on polystyrene standards in 70/30 CH 2 Cl 2 /HFIP mobile phase. [39] This result is in the range of other TPA copolyesters like TPA‐62 %CHDM/38 %EG (PCTG), which has M w 45.7 kDa and M n 18.7 kDa [40] and PET which has M w 49.5 kDa and M n 20.1 kDa [41] by GPC. For TPA‐TMCD/CHDM polymer, the degree of polymerization (DP) can be determined by 1 H NMR in CHCl 3 ‐d/trifluoroacetic acid‐d by dividing the sum of integrals of cis (4.75 ppm) and trans (4.91 ppm) methine peaks by end group (4.05 ppm) for TMCD units (DP tmcd ) and the sum of integrals of cis (4.43 ppm) and trans (4.32 pm) methyl peaks by end group (4.05 ppm) for CHDM units (DP chdm ).…”

“…HFIP is an excellent polar protic solvent for the solubilizing of terephthalic acid class of polyesters. [39] The intrinsic viscosity of the copolyesters are in the range of 0.5–0.8 dL/g in phenol/tetrachloroethane at 23 °C. [23] TPA‐TMCD/CHDM copolyester (Tritan TX1000) has weight‐average molecular weight ( M w ) of 20 kDa, number‐average ( M n ) 10.5 kDa and dispersity ( M w /M n ) of 1.97.…”

“…[45] Adding 10 % Cyasorb 1164, a benzoxazinone UV absorber, reduced free‐radical induced cross‐linking of TPA‐CHDM/TMCD (PCTT) film on UV irradiation. [39] …”

Aging of 3D Printed Polymers under Sterilizing UV-C Radiation

“…Zhang et al, highlighted the effects of UV-C irradiation on PLA, also concluding that UV accelerates degradation process and that the molecular weight loss increases linearly with exposure time [45]. For PETG, Arangdad et al, studied the impact of UV exposure on degradation and the influence of various UV photostabilizers in reducing this degradation [46].…”

X‐ray photoelectron spectroscopy study on the photodegradation of copolyester model compounds

“…X-ray photoelectron spectroscopy (XPS) has been used to study changes in material surfaces which are principally changes of absolute C/O intensity ratio on polymers such as PET, [13][14][15][16] poly(L-lactic acid) (PLLA), 17 polymethylmethacrylate (PMMA) and blends of polycarbonate and acrylonitrile butadiene styrene. 18 Depth analysis of chemical bonding states of polymers is determined by photoelectron mean free path using conventional XPS 19 instruments that can be enhanced using hard XPS.…”