Epoxy Resin Based on Poly(ethylene terephthalate) Waste: Synthesis and Characterization

Abstract

Aromatic epoxy resin based on poly(ethylene terephthalate), PET, was synthesised by glycolysis of PET with different ratios of diethanolamine or triethanolamine and manganese acetate as a catalyst. The glycolyzed products were reacted with epichlorohydrine to prepare a series of di- and tetraglycidyl epoxy resins with different molecular weights. P-Phenylene diamine and diaminodiphenylether were used as curing agents. The curing reactions and thermal properties of cured aromatic epoxy resins were investigated. Curing and post cure peaks were observed in dynamic DSC thermograms. The crosslinked network was thermally stable up to 470oC. Preliminary tests indicate that the resins exhibit superior adhesion properties.

Synthesis of bisphenol a novolac epoxy resins for coating applications

“…The data listed in Table V, indicate that the alkali and acid resistances were decreased when the mixing ratios between novolacs bisphenol A epoxy resin with AEP were decreased. This can be referred to the high ability to form dangling chains which agree with the results discussed in previous work 11–13…”

“…On the other hand, the decreasing of hardener content decreases cross‐link density of network and increase the attack of ester groups of network to acidic and alkaline solutions. The lower acid and base resistance of cured BPE‐5 and BPE‐7.5 can be referred to the formation of dangling chains (bonded from end and free from another end) which increase the attack of ester and amide groups with both acid and alkali media 11. The data listed in Table V, indicate that the alkali and acid resistances were decreased when the mixing ratios between novolacs bisphenol A epoxy resin with AEP were decreased.…”

“…These behaviors indicate that the ratios of cross‐linking agent affect the mechanical properties of coatings. This behavior leads to speculate that the high cross‐linking density networks decreases the mechanical properties of the formed network 11–13. The variation of hardness results (by pencil test) from soft (minimum cross‐links) to hard coatings (maximum cross‐link‐density) indicate that the best results were determined at low mixing mol ratio for epoxy : hardener systems.…”

“…The disappearance of OH peak at 4.7 ppm in spectrum of BP, Fig. 5(b), and appearance of two peaks at 2.82 ppm (CH 2 epoxy), 2.94 ppm (OCH 2 epoxy), and 3.43 ppm (CH epoxy) indicates the formation of glycidyl ether group 11–13…”

“…Then the panels were subjected to different testing procedure to evaluate their mechanical properties and their durability. Adhesion strength (pull‐off ASTM D 4541 ), mechanical properties (pencil hardness ASTM D3363 , impact ASTM D 2794 , T‐ bend tests ASTM D 522 , chemical resistances (hot water ASTM D 870 , acid and alkali resistance ASTM D 1647 and solvent resistance ASTM D 2792 ) were measured as reported in a previous study 11–13. The coated panels were evaluated for salt‐spray resistance in accordance with ASTM B117 .…”

Synthesis of bisphenol a novolac epoxy resins for coating applications

“…The data listed in Table V, indicate that the alkali and acid resistances were decreased when the mixing ratios between novolacs bisphenol A epoxy resin with AEP were decreased. This can be referred to the high ability to form dangling chains which agree with the results discussed in previous work 11–13…”

“…On the other hand, the decreasing of hardener content decreases cross‐link density of network and increase the attack of ester groups of network to acidic and alkaline solutions. The lower acid and base resistance of cured BPE‐5 and BPE‐7.5 can be referred to the formation of dangling chains (bonded from end and free from another end) which increase the attack of ester and amide groups with both acid and alkali media 11. The data listed in Table V, indicate that the alkali and acid resistances were decreased when the mixing ratios between novolacs bisphenol A epoxy resin with AEP were decreased.…”

“…These behaviors indicate that the ratios of cross‐linking agent affect the mechanical properties of coatings. This behavior leads to speculate that the high cross‐linking density networks decreases the mechanical properties of the formed network 11–13. The variation of hardness results (by pencil test) from soft (minimum cross‐links) to hard coatings (maximum cross‐link‐density) indicate that the best results were determined at low mixing mol ratio for epoxy : hardener systems.…”

“…The disappearance of OH peak at 4.7 ppm in spectrum of BP, Fig. 5(b), and appearance of two peaks at 2.82 ppm (CH 2 epoxy), 2.94 ppm (OCH 2 epoxy), and 3.43 ppm (CH epoxy) indicates the formation of glycidyl ether group 11–13…”

“…Then the panels were subjected to different testing procedure to evaluate their mechanical properties and their durability. Adhesion strength (pull‐off ASTM D 4541 ), mechanical properties (pencil hardness ASTM D3363 , impact ASTM D 2794 , T‐ bend tests ASTM D 522 , chemical resistances (hot water ASTM D 870 , acid and alkali resistance ASTM D 1647 and solvent resistance ASTM D 2792 ) were measured as reported in a previous study 11–13. The coated panels were evaluated for salt‐spray resistance in accordance with ASTM B117 .…”

Synthesis of bisphenol a novolac epoxy resins for coating applications

“…The data listed in Table V, indicate that the alkali and acid resistances were decreased when the mixing ratios between novolacs bisphenol A epoxy resin with AEP were decreased. This can be referred to the high ability to form dangling chains which agree with the results discussed in previous work 11–13…”

“…On the other hand, the decreasing of hardener content decreases cross‐link density of network and increase the attack of ester groups of network to acidic and alkaline solutions. The lower acid and base resistance of cured BPE‐5 and BPE‐7.5 can be referred to the formation of dangling chains (bonded from end and free from another end) which increase the attack of ester and amide groups with both acid and alkali media 11. The data listed in Table V, indicate that the alkali and acid resistances were decreased when the mixing ratios between novolacs bisphenol A epoxy resin with AEP were decreased.…”

“…These behaviors indicate that the ratios of cross‐linking agent affect the mechanical properties of coatings. This behavior leads to speculate that the high cross‐linking density networks decreases the mechanical properties of the formed network 11–13. The variation of hardness results (by pencil test) from soft (minimum cross‐links) to hard coatings (maximum cross‐link‐density) indicate that the best results were determined at low mixing mol ratio for epoxy : hardener systems.…”

“…The disappearance of OH peak at 4.7 ppm in spectrum of BP, Fig. 5(b), and appearance of two peaks at 2.82 ppm (CH 2 epoxy), 2.94 ppm (OCH 2 epoxy), and 3.43 ppm (CH epoxy) indicates the formation of glycidyl ether group 11–13…”

“…Then the panels were subjected to different testing procedure to evaluate their mechanical properties and their durability. Adhesion strength (pull‐off ASTM D 4541 ), mechanical properties (pencil hardness ASTM D3363 , impact ASTM D 2794 , T‐ bend tests ASTM D 522 , chemical resistances (hot water ASTM D 870 , acid and alkali resistance ASTM D 1647 and solvent resistance ASTM D 2792 ) were measured as reported in a previous study 11–13. The coated panels were evaluated for salt‐spray resistance in accordance with ASTM B117 .…”

Synthesis of bisphenol a novolac epoxy resins for coating applications

“…The data listed in Table V, indicate that the alkali and acid resistances were decreased when the mixing ratios between novolacs bisphenol A epoxy resin with AEP were decreased. This can be referred to the high ability to form dangling chains which agree with the results discussed in previous work 11–13…”

“…On the other hand, the decreasing of hardener content decreases cross‐link density of network and increase the attack of ester groups of network to acidic and alkaline solutions. The lower acid and base resistance of cured BPE‐5 and BPE‐7.5 can be referred to the formation of dangling chains (bonded from end and free from another end) which increase the attack of ester and amide groups with both acid and alkali media 11. The data listed in Table V, indicate that the alkali and acid resistances were decreased when the mixing ratios between novolacs bisphenol A epoxy resin with AEP were decreased.…”

“…These behaviors indicate that the ratios of cross‐linking agent affect the mechanical properties of coatings. This behavior leads to speculate that the high cross‐linking density networks decreases the mechanical properties of the formed network 11–13. The variation of hardness results (by pencil test) from soft (minimum cross‐links) to hard coatings (maximum cross‐link‐density) indicate that the best results were determined at low mixing mol ratio for epoxy : hardener systems.…”

“…The disappearance of OH peak at 4.7 ppm in spectrum of BP, Fig. 5(b), and appearance of two peaks at 2.82 ppm (CH 2 epoxy), 2.94 ppm (OCH 2 epoxy), and 3.43 ppm (CH epoxy) indicates the formation of glycidyl ether group 11–13…”

“…Then the panels were subjected to different testing procedure to evaluate their mechanical properties and their durability. Adhesion strength (pull‐off ASTM D 4541 ), mechanical properties (pencil hardness ASTM D3363 , impact ASTM D 2794 , T‐ bend tests ASTM D 522 , chemical resistances (hot water ASTM D 870 , acid and alkali resistance ASTM D 1647 and solvent resistance ASTM D 2792 ) were measured as reported in a previous study 11–13. The coated panels were evaluated for salt‐spray resistance in accordance with ASTM B117 .…”