Physical properties of polydimethylsiloxane-containing elastomers and their electrospun nanofibre mats

A series of polydimethylsiloxane-containing elastomers (Selastomers) were synthesised from 4,4′-diphenylmethane diisocyanate (MDI), 1,4-butanediol (1,4-BD) and polydimethylsiloxane (PDMS). Through TGA analysis, S elastomers exhibited a four-stage degradation. The first and second stages resulted from the degradation of hard segment; the complicated degradation behaviour in the stages is associated with two hard-segment structures in the S elastomers. The third stage was the decomposition of PDMS, in which a cyclosiloxane degradation product was formed; subsequently, at a higher temperature it proved to be macrocyclics, which were degraded in the vicinity of 550 °C Obviously, the degradation of S elastomers differed from the two-stage degradation of conventional polyurethane. Compared to conventional polyurethane, S elastomers presented better mechanical properties, showing the strength and elongation at break about 5.6-20.6 MPa and 550-830 96, respectively. With the better mechanical properties of S elastomers, nano-structured fibre mats were produced by electrospinning. Fibre morphology was observed by SEM and the effects of processing variables, including solution concentrations and voltages, on the morphology were evaluated.