Vulcanization and crosslinking in elastomers

The effect of γ-irradiation on acrylonitrile–butadiene rubber NBR seal materials with different antioxidants

The efficiency of six polyfunctional monomers (PFMs) as crosslinking coagents for radiation vulcanization of acrylonitrile–butadiene rubber (NBR) by electron beam was studied. It was found that among the polyfunctional monomers having same functionality, short chain PFMs are better than long chain PFMs. Comparison is also made to select more efficient PFMs among methacrylates and acrylates for radiation vulcanization of NBR. The methacrylate monomers showed preference over acrylate monomers. Physical properties of NBR are greatly improved by PFMs at lower doses. Radiation vulcanization of NBR with diethyleneglycol dimethacrylate (2G), at 20 kGy showed results similar to those obtained by conventionally vulcanized NBR.

Radiation vulcanization of acrylonitrile–butadiene rubber with polyfunctional monomers

Effect of concentration of polyfunctional monomers on physical properties of acrylonitrile–butadiene rubber under electron-beam irradiation

The effect of acrylonitrile content on the physical properties of acrylonitrile–butadiene rubber (NBR) under electron beam induced vulcanization was studied Diethylene glycol dimethacrylate (2G) and trimethylol propane trimethacrylate (TMPT) were used as polyfunctional monomers (containing two or more polymerizable CC double bonds in a molecule, PFMs) to lower the irradiation dose The effect of acrylonitrile content (AN) on physical properties was pronounced only at low doses where the crosslink densities were not too high The crosslink density in the polymer matrix is affected by the nature of polyfunctional monomers (PFMs) and acrylonitrile content of NBR In radiation vulcanized NBR, the crosslink density in the matrix is increased by increasing AN content with corresponding decrease in swelling

Effect of acrylonitrile content on physical properties of electron beam irradiated acrylonitrile–butadiene rubber

The efficiency of seven functional monomers toward Styrene-Butadiene rubber (SBR) were following the order, Tetramethylol methane tetraacrylate (ATMMT) = Tolyene diiaocynate (UA306T)>Trimethylol propane trimethacrylate (TMPT)>Diethylene glycol dimethacrylate (2G)>Dipentaerithrol hexaacrylate (DPE6A)>Hexamethylene diisocynate (UA101H))>Triallyl cynurat (TAC). Also it was found that low absorption of ATMMT has been overcame at low dose. The observed clear and transperant sheets indicate that the reaction was complete

Physical properties of styrene-butadiene rubber radiation vulcanized with functional monomers

The effect of styrene content on the properties of electron irradiation-vulcanized SBR loaded with carbon black was pronounced only at low irradiation doses where the crosslinking densities were not so high. At high doses, no effect was observed especially for SBR containing ZnO. It was also observed that ZnO (3 phr) increased the tensile strength of SBR containing 23.5 wt.-% styrene by 20% at 20 kGy irradiation dose, compared to 5% at higher doses for SBR containing 46 wt.-% styrene. However, the increase in tensile strength by ZnO for loaded SBR (23.5%) was almost 17% at all irradiation doses. Besides, tear strength, abrasion resistance and elongation at break were remarkably improved. The high efficiency of ZnO toward SBR (23.5%) may be attributed to the higher butadiene content. The behavior of SBR (46%) at 20 kGy was surprising, since both tensile strength and elongation at break were almost maximum.



Der Einflus des Styrolgehalts auf die Eigenschaften von elektronenstrahlvernetztem, rusgefulltem Styrol-Butadien-Kautschuk (SBR) war nur bei niedrigen Strahlungsdosen, d. h. geringen Vernetzungsgraden, ausgepragt. Bei hohen Dosen wurde kein Effekt beobachtet, insbesondere fur ZnO-enthaltenden SBR. Es wurde auserdem festgestellt, das ZnO (3 phr) die Zugfestigkeit von SBR mit einem Styrolgehalt von 23,5 Gew.-% bei 20 kGy um 20% verbesserte, verglichen mit SBR mit 46 Gew.-% Styrol. Die Zunahme der Zugfestigkeit fur gefullten SBR (23,5%) betrug bei allen Strahlungsdosen nahezu 17%. Daneben waren Reisfestigkeit, Abrasionswiderstand und Bruchdehnung erheblich verbessert. Die hohe Effizienz von ZnO bei SBR (23,5%) konnte auf dessen hoheren Butadiengehalt zuruckzufuhren sein. Das mechanische Verhalten von SBR (46%) bei 20 kGy war uberraschend, da sowohl Zugfestigkeit als auch Bruchdehnung nahezu maximal waren.

M. M. Abdel Aziz

Papers

Physical properties of styrene-butadiene rubber radiation vulcanized with functional monomers

Effect of styrene content and ZnO-stearic acid on the mechanical properties of radiation-vulcanized styrene-butadiene rubber (SBR)