Role of Molecular Weight in the Mechanical Properties and Charge Transport of Conjugated Polymers Containing Siloxane Side Chains was written by Huang, Gang;Wu, Ning;Wang, Xiaohong;Zhang, Guobing;Qiu, Longzhen. And the article was included in Macromolecular Rapid Communications in 2022.Electric Literature of C4H4BrNO2 This article mentions the following:
The mol. weight is a key factor affecting the properties of conjugated polymers. To determine the critical mol. weights of conjugated polymers modified with siloxane side chains, poly(diketo-pyrrolopyrrole-selenophene) (PTDPPSe-5Si) samples with mol. weights ranging from 20 to 350 kDa are synthesized. The critical mol. weight of the polymer is determined in the range of 60-100 kDa by testing the viscosity of the solution When the mol. weight of the 27-60 kDa polymers is below the critical mol. weight, they exhibit a high crystallinity and low ductility. When the mol. weight of the 100 kDa polymer reaches the critical mol. weight, the crystallinity decreases, and the ductility increases. As the mol. weight increases, the polymer film also gradually changes from brittle to ductile. Furthermore, when the mol. weight of the 315 kDa polymer is much higher than the critical mol. weight, the film exhibits a significant ductility, which results in the polymer films showing no pronounced cracks after high-percentage stretching. Addnl., due to the oriented alignment of the mol. chains caused by stretching, the carrier mobility in the parallel direction becomes 2.14-fold of the initial film. In the experiment, the researchers used many compounds, for example, 1-Bromopyrrolidine-2,5-dione (cas: 128-08-5Electric Literature of C4H4BrNO2).
1-Bromopyrrolidine-2,5-dione (cas: 128-08-5) belongs to organobromine compounds. Bromine is more electronegative than carbon (2.9 vs 2.5). Consequently, the carbon in a carbon闂佺偨鍎茶ぐ绲﹐mine bond is electrophilic, i.e. alkyl bromides are alkylating agents. Many of the alkyl bromine derivatives are excellent alkylating agents since bromides are good leaving groups. Tribromides, like tetrabutylammonium tribromide, are used as a solid source of bromine. N-bromosuccimide (NBS) is used for the selective bromination of allylic bonds.Electric Literature of C4H4BrNO2
Referemce:
Bromide – Wikipedia,
bromide – Wiktionary