有机硅二醇对硅氧烷基聚氨酯弹性体的影响
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摘要
以不同比例的PDMS(聚二甲基硅氧烷)/PPG(聚丙二醇)为混合软段,采用两步法合成了一系列硅氧烷基聚氨酯弹性体(SiPU)。通过FTIR(傅里叶变换红外)、接触角分析、耐酸碱介质试验、耐湿热老化试验、DMA(动态力学分析)和TGA(热重分析),研究了所制SiPU的结构、力学性能、表面性能、耐酸碱介质性能、耐湿热老化性能及热性能。结果表明:PDMS的含量明显影响SiPU的形态和性能:随PDMS的含量增大,接触角逐渐增大,材料的疏水性增强,拉伸强度和扯断伸长率先增大后减小,硬度、模量和撕裂强度逐渐提高,当w(PDMS)在10%～20%时显示最高的拉伸强度和断裂伸长率;SiPU耐碱性介质性能优于耐酸性介质性能,随PDMS的含量增大,耐酸性介质性能的拉伸强度保持率逐渐提高,耐碱性介质性能以w(PDMS)=20%最好;耐湿热老化性能则以w(PDMS)在25%～30%最好;在软段中引入适量的PDMS,有利于软硬段的微相分离和PU热稳定性的改善;PDMS含量过高会使PU的力学性能和热性能降低。
Using the PDMS(poly(dimethyl siloxane))/PPG(poly(propylene glycol)) with different ratios as the mixed soft segment, a series of siloxane-based polyurethane(SiPU) elastomers were synthesized by two-step method. The structures, mechanical performance, surface performance, acidic and alkaline media resistance, hygrothermal aging resistance and thermal performance of the prepared SiPU were investigated by FTIR(Fourier transform infrared), contact angle analysis, acidic and alkaline media resistance test,hygrothermal aging resistance test, DMA(dynamic mechanical analysis) and TGA(thermogravimetric analysis). The results show that the PDMS content can significantly affect the morphology and performance of SiPU. With increasing of PDMS content, the contact angle gradually increases, the hydrophobicity of the materials strengthens, the tensile strength and elongation at break first increase and then decrease, the hardness, modulus and tear strength gradually increase. When w(PDMS) is 10%～20%, the tensile strength and elongation at break are maximum. The alkaline medium resistance performance of SiPU is superior to its acidic medium resistance performance, with increasing of PDMS content, the tensile strength retention rate for acidic medium resistance gradually increases, the alkaline medium resistance is the optimal when w(PDMS)=20%, the hygrothermal aging resistance performance is optimal when w(PDMS) is 25%～30%.Introducing appropriate amount of PDMS into the soft segment is advantageous to the micro-phase separation of the soft and rigid segments and the improvement of the PU thermal stability. The exorbitant content of PDMS can reduce the mechanical and thermal performance of PU.
Using the PDMS(poly(dimethyl siloxane))/PPG(poly(propylene glycol)) with different ratios as the mixed soft segment, a series of siloxane-based polyurethane(SiPU) elastomers were synthesized by two-step method. The structures, mechanical performance, surface performance, acidic and alkaline media resistance, hygrothermal aging resistance and thermal performance of the prepared SiPU were investigated by FTIR(Fourier transform infrared), contact angle analysis, acidic and alkaline media resistance test,hygrothermal aging resistance test, DMA(dynamic mechanical analysis) and TGA(thermogravimetric analysis). The results show that the PDMS content can significantly affect the morphology and performance of SiPU. With increasing of PDMS content, the contact angle gradually increases, the hydrophobicity of the materials strengthens, the tensile strength and elongation at break first increase and then decrease, the hardness, modulus and tear strength gradually increase. When w(PDMS) is 10%～20%, the tensile strength and elongation at break are maximum. The alkaline medium resistance performance of SiPU is superior to its acidic medium resistance performance, with increasing of PDMS content, the tensile strength retention rate for acidic medium resistance gradually increases, the alkaline medium resistance is the optimal when w(PDMS)=20%, the hygrothermal aging resistance performance is optimal when w(PDMS) is 25%～30%.Introducing appropriate amount of PDMS into the soft segment is advantageous to the micro-phase separation of the soft and rigid segments and the improvement of the PU thermal stability. The exorbitant content of PDMS can reduce the mechanical and thermal performance of PU.
引文
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[2]ADHIKARI R,GUNATILLAKE P A,MCCARTHY S J,et al.Effect of chain extender structure on the properties and morphology of polyurethanes based on H12MDI and mixed macrodiols(PDMS-PHMO)[J].J Appl Polym Sci,1999,74(12):2 979-2 989.
[3]STANCIU A,AIRINEI A,TIMPU D,et al.Polyurethane/polydimethylsiloxane segmented copolymers[J].Eur Polym J,1999,35(11):1 959-1 965.
[4]WANG L F,JI Q,GLASS T E,et al.Synthesis and characterization of organosiloxane modified segmented polyether polyurethanes[J].Polymer,2000,41(13):5 083-5 093.
[5]ADHIKARI R,GUNATILLAKE P A,MCCARTHY S J,et al.Low-modulus siloxane-polyurethanes.PartⅡ.Effect of chain extender structure on properties and morphology[J].J Appl Polym Sci,2003,87(7):1 092-1100.
[6]SHETH J P,ANEJA A,WILKES G L,et al.Influence of system variables on the morphological and dynamic mechanical behavior of polydimethylsiloxane based segmented polyurethane and polyurea copolymers:Acomparative perspective[J].Polymer,2004,45(20):6 919-6 932.
[7]ADHIKARI R,GUNATILLAKE P A,MCCARTHY SJ,et al.Mixed macrodiol-based siloxane polyurethanes:effect of the comacrodiol structure on properties and morphology[J].J Appl Polym Sci,2000,78(5):1 071-1 082.
[8]CHOI T,WEKSLER J,PADSALGIKAR A,et al.Influence of soft segment composition on phase-separated microstructure of polydimethylsiloxane-based segmented polyurethane copolymers[J].Polymer,2009,50(10):2 320-2 327.