Gelation kinetics of RAFT radical copolymerization of methacrylate and dimethacrylate was written by Yu, Qiang;Gan, Qian;Zhang, Hongwen;Zhu, Shiping. And the article was included in ACS Symposium Series in 2009.Name: Benzyl benzodithioate This article mentions the following:
The gelation kinetics and network development in the RAFT copolymerization of oligo(ethylene glycol) Me ether methacrylate (OEGMEMA) and oligo(ethylene glycol) dimethacrylates (OEGDMA) were investigated using differential scanning calorimetry, solvent extraction/swelling technique, and dynamic mech. anal. A significant autoacceleration was observed in the RAFT copolymerization processes. For the RAFT systems with 2.56, 5.26, 8.11, and 11.11 mol% OEGDMA, the vinyl conversions at the onset of autoacceleration were ∼26, 21, 17, and 15%, resp., very close to the corresponding microgel points. This suggested that the highly branched chains and gels restricted the mobilities of propagating radicals and RAFT-capped chains, resulting in the autoacceleration. The gelation behavior in the RAFT process was different from that in conventional free radical polymerization The slow chain growth in the RAFT process allowed sufficient chain relaxation and uniform distribution of reacting species, which reduced intramol. crosslinking and limited microgel formation. Increasing OEGDMA concentration level resulted in earlier gelation and faster network development, giving rise to network products with higher crosslinking densities, higher glass transition temperatures, and deteriorated structural homogeneities. In the experiment, the researchers used many compounds, for example, Benzyl benzodithioate (cas: 27249-90-7Name: Benzyl benzodithioate).
Benzyl benzodithioate (cas: 27249-90-7) belongs to esters. Esters are widespread in nature and are widely used in industry. In nature, fats are in general triesters derived from glycerol and fatty acids. Esters are responsible for the aroma of many fruits, including apples, durians, pears, bananas, pineapples, and strawberries. Many esters have the potential for conformational isomerism, but they tend to adopt an s-cis (or Z) conformation rather than the s-trans (or E) alternative, due to a combination of hyperconjugation and dipole minimization effects. The preference for the Z conformation is influenced by the nature of the substituents and solvent, if present. Lactones with small rings are restricted to the s-trans (i.e. E) conformation due to their cyclic structure.Name: Benzyl benzodithioate
Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics