SYNOPSISPara-phenylenediamine ( PD) was chemically attached to depolymerized natural rubber by a photochemical reaction . The rubber bound PD was characterized by TLC, 1H-NMR, IR, and TGA. The efficiency and permanence of the bound PD were compared with conventional antioxidants in NBR vulcanizates . The rubber bound PD was found to be less volatile and more resistant to water and oil extraction . The vulcanizates showed improved aging resistance in comparison to vulcanizates containing conventional antioxidants. The liquid rubber bound antioxidant reduces the amount of plasticizer required for compounding .
Maleic anhydride was chemically attached to depolymerized natural rubber by a photochemical reaction. The product Carboxy Terminated Liquid Natural Rubber (CTNR) was characterized by 1 H-NMR, IR, GPC, and TGA. The efficiency and permanence of CTNR were compared with conventional plasticizers in NBR vulcanizates. This polymeric plasticizer was found to be less volatile and more resistant to oil extraction. The vulcanizates showed improved aging resistance compared to vulcanizates containing conventional plasticizers.
SUMMARYAntioxidants were attached to hydroxy-terminated liquid natural rubber by modified Friedel-Crafts alkylation reaction using anhydrous zinc chloride as catalyst. The rubber bound antioxidants were found to be less volatile and less extractable compared to conventional antioxidants. The bound antioxidants were tried both in latex compounds and dry rubber compounds. The vulcanizates showed improved ageing resistance compared to vulcanizates based on conventional antioxidants.
ZUSAMMENFASSUNG:Antioxidantien wurden in einer modifizierten Friedel-Crafts-Reaktion mit wasserfreiem Zinkchlorid als Katalysator an Fliissig-Naturkautschuk mit Hydroxy-Endgruppen gebunden. Die immobilisierten Antioxidantien waren weniger fluchtig und extrahierbar als konventionelle Antioxidantien. Sie wurden sowohl einem Latex als auch trockenem Kautschuk zugesetzt; die daraus hergestellten Vulkanisate zeigten eine bessere Alterungsbestandigkeit als Vulkanisate mit konventionellen Antioxidantien.
Antioxidants were attached to hydroxy‐terminated liquid natural rubber by modified Friedel‐Crafts alkylation reaction using anhydrous zinc chloride as catalyst. The rubber bound antioxidants were found to be less volatile and less extractable compared to conventional antioxidants. The bound antioxidants were tried both in latex compounds and dry rubber compounds. The vulcanizates showed improved ageing resistance compared to vulcanizates based on conventional antioxidants.
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