Abstract:

Cellulose triacetate (CTA) is a kind of cellulose derivatives with high strength, and the modified CTA can be applied in the separation, adsorption and sensors, however, it is difficult to modify it by chemical initiated grafting. In this article, CTA membranes were successfully modified with poly(glycidyl methacrylate) (PGMA) by the combination of radiation-initiated grafting and the reversible addition-fragmentation chain transfer (RAFT) polymerization method. Effects of absorbed dose, concentration of GMA and amount of RAFT agent on degree of grafting were studied. The structure, morphology and surface property of the CTA membranes before and after grafting were investigated by Flourier transform infrared spectrometer (FT-IR), scanning electronic microscopy (SEM) and contact angle test. The results show that, for a higher degree of grafting and better morphology, the optimal conditions could be found at absorbed dose of 10~12 kGy, with mass fraction 30% of GMA and molar ratio 1/400 of RAFT agent and GMA. The grafted CTA membrane with the highest degree of grafting (41%) and the narrow distribution of relative molecular mass (1.33) can be obtained under suitable conditions. After grafting, the hydrophobicity of CTA membranes increases. The work provides a simple method to prepare grafted CTA with controlled structures. Compared with traditional radiation-initiated grafting, the radiation-initiated RAFT reaction conditions are easier to be controlled in RAFT-mediated grafting process, and the grafted polymer chains are better-distributed, which benefits further functionalization and practical application of modified CTA membranes.

Key words: cellulose triacetate, radiation-induced grafting, reversible addition-fragmentation chain transfer polymerization