| The styrene/butadiene/styrene block copolymer(SBS)membrane materials filled with corn straw lignin were prepared through solution casting.The effects of lignin on the performances of SBS,including mechanical property,combustion performance,agingresistance performance(thermal oxidation aging,ultraviolet aging and damp-heat aging)were studied by mechanical property testing,dynamic mechanical analysis(DMA),cone calorimeter test(CONE),infrared spectrum analysis(FTIR)and X-ray electron energy spectrum(XPS)and so on.The tensile test results showed that the mechanical properties of SBS elastomer could be improved by the filling of lignin.The tensile strength and elongation at break for the SBS with 6% lignin were 22.77 MPa and 2407%.Compared with the unfilled SBS,the tensile strength and elongation at break of modified SBS increased for 32% and 15% respectively.The DMA analysis indicated that the storage modulus and the glass-transition temperature(Tg)were improved by filling with lignin.The cone calorimeter test results showed that the total heat release was reduced by filling with lignin,and the same as specific extinction area.The rate of the mass loss was slower,which indicated that the flame retardant property of SBS was improved by filling with corn straw lignin.Compared with pure SBS,the tensile strength of the SBS filled with lignin decreased for 67.37% instead of 74.53%,and the elongation at break decreased for 46.65% instead of 72.89% in the same thermal-oxidation aging time.The DMA analysis indicated that the change of the glass-transition temperature(Tg)slow down by filling with lignin.The FTIR and XPS analysis results showed that lignin restrained the generation of the oxygen-containing groups in the thermal-oxidation aging.In the temperature range of 140?~160?,after aging time of two hours,compared with the unmodified SBS,the tensile strength of the SBS elastomer filling modified with lignin has fallen from 38.57% to 16.29%,the elongation at break declined from 35.96% to 8.30%,and the glass transition temperature for rubber piece drop from 7.06% to 2.32%.Filling modification of SBS with lignin would retard the change degree of the glass transition temperature for the rubber piece of SBS and the increase of the content of oxygen on the surface of SBS resulted by the thermal oxidation aging effectively.Lignin filling modification of SBS has played an important role in anti-aging,which improved the aging resistance performance of SBS.The tensile strength and the elongation at break of SBS elastomer modified with lignin changed from 60.76% to 27.09% and from 70.51% to 18.44% after 10 days ultraviolet aging compared with pure SBS respectively.Dynamic mechanical analysis showed that the degradation of SBS was main reaction during the ultraviolet aging(UV aging)process of SBS,and for the SBS filled with lignin,the cross-linking reaction was main reaction in the initial aging stage and the degradation reaction was dominant in the later aging stage.The change degree of glass transition temperature and loss factor for SBS were decreased after the addition of lignin,which embodied the anti-aging effect for SBS.FTIR and XPS analysis results showed that the decomposition of lignin plays a role in delaying the aging of SBS elastomer to a certain extent during the ultraviolet aging process.The UV aging resistance of SBS elastomer was improved by filling modified with lignin.The tensile strength of SBS elastomer decreased from 17.28 MPa to 5.60 MPa,while that of SBS elastomer modified with 6wt% lignin decreased from 22.77 MPa to 12.20 MPa.The percent of decreasing was 67.60% and 46.42% after damp-heat aging for 10 days.The elongation at break of SBS elastomer decreased from 2095% to 605%,while that of SBS elastomer modified with 6wt% lignin decreased from 2407% to 1437%.The percent of decreasing was 71.12% and 40.30%.Dynamic mechanical analysis showed that the crosslinking reaction was main reaction in the initial aging stage and the degradation reaction was dominant in the later aging stage during the damp-heat aging process of SBS,but for the SBS filled with lignin,the cross-linking reaction was main reaction in the whole aging stage in the experimental time range.The change degree of glass transition temperature and loss factor for SBS were decreased after the addition of lignin,which embodied the anti-aging effect for SBS.FTIR analysis results showed that the decomposition of lignin plays a role in delaying the aging of SBS elastomer to a certain extent during the aging process.The result shows the damp-heat aging resistance of SBS elastomer was improved by filling modified with lignin. |
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