【作者】 宗建平；

【导师】 张庆思；

【作者基本信息】 山东轻工业学院 ， 应用化学， 2010， 硕士

【摘要】 有机硅改性聚氨酯水分散体既保持了聚氨酯耐磨、抗撕裂的特点,又具有有机硅耐水性及柔韧性好的优点,是目前改性聚氨酯水分散体的研究热点。已有的相关报道多集中于聚硅氧烷(PDMS)嵌段改性聚氨酯的研究,对单端双羟烃基聚硅氧烷接枝改性聚氨酯水分散体的研究报道极少。本文以自制的单端双羟烃基聚硅氧烷和双端双羟烃基聚硅氧烷为改性原料,合成了聚硅氧烷接枝和嵌段改性聚氨酯水分散体,并对比研究了两种改性聚氨酯的性能。分别以自制的α-丁基-ω-{3-[2-羟基-3-(N-甲基-N-羟乙胺基)丙氧基]丙基}聚二甲基硅氧烷(PDMSa)和α,ω-双[3-(1-甲氧基-2-羟基-丙氧基)丙基]封端聚硅氧烷(PDMSb)为改性原料、以2,4-甲苯二异氰酸酯为硬段、聚醚210、聚醚220等为软段,二羟甲基丙酸为离子中心、二乙烯三胺为扩链剂,采用丙酮法合成了聚硅氧烷接枝改性聚氨酯水分散体(GPU)和聚硅氧烷嵌段改性聚氨酯水分散体(BPU)。利用红外光谱(FT-IR)对其结构进行了表征,并研究了PDMS含量、分子量及加料顺序对改性聚氨酯水分散体各性能的影响。利用透射电镜(TEM)及环境扫描电镜(SEM)观察了水分散体的颗粒形态、胶膜断面微观形貌,并分析了胶膜各层元素组成。FT-IR谱图显示,PDMSa、PDMSb均成功连接到聚氨酯分子链中。PDMS分子量相同时,随着其含量增加,GPU和BPU的粘度和粒径均增加,胶膜的耐水及耐甲苯性能提高,但光泽度、拉伸强度下降。当PDMS含量为9%时,随着其分子量的增加,GPU水分散体粘度下降,胶膜的耐水及耐甲苯性能提高。当PDMSa分子量为2000左右时,接枝改性胶膜的接触角达到最大值(98.7°)、吸水率达到最小值(15.5%)、断裂伸长率达到最大(279.4%)。对BPU而言,随着PDMSb分子量的增加,BPU的粘度及颗粒粒径增大;胶膜的耐水性能提高,耐甲苯性能下降,接触角增加,光泽度、拉伸强度减小,断裂伸长率增大。透射电镜图片显示,两种改性聚氨酯水分散体的颗粒形态均不规则,扫描电镜结果表明,两种胶膜的均存在相分离现象,元素组成分析表明,PDMS有表面富集作用。前后加料方式的对比研究表明,采用前加料方式合成样品的耐水性、耐甲苯性及力学性能较好。两种改性聚氨酯的性能对比研究表明,在聚硅氧烷分子量相当、含量相同条件下,PDMSa接枝改性聚氨酯耐水及耐甲苯性能更好。在实际应用时,可选用分子量为2000左右的PDMSa,含量为7%,采用前加料法,可得到综合性能较好的聚硅氧烷改性聚氨酯水分散体。更多还原

【Abstract】 Recently, much attention has been drawn to polysiloxane modified polyurethanes(PU), which have both the good water resistance and flexibility of polysiloxanes and the good mechanical property and abrasion resistance of polyurethanes. However,most of work focused on the perperties of PU dispersions modified by polysiloxane with block copolymerizeration (BPU) and few on PU dispersions modified by polydimethylsiloxane with graft copolymerization (GPU). We synthesized both GPU and BPU in wich PDMS was self-made. In addition, comparative study on their properties was taken.In this work,α-butyl-ω-{3-[2-hydroxy-3-(N-methyl-N-hydroxy-ethylamino)-prop- -oxy]propyl}polydimethylsiloxane(PDMSa) andα,ω-bis(3-(1- methoxy-2-hydroxypr- -opyl) terminated polysiloxanes(PDMSb) were used to synthesize GPU and BPU. In the experiment, toluene 2, 4-diisocyanate was used as hard segment, polypropylene glycol with molecular weight 1000 and 2000 as soft segment, dimethylol propionic acid as the anionic center and diethylenetriamine as the chain extender. The effects of PDMS’s structure, content and molecular weight on properties of copolymer were studied. The structures and morphologies of PU dispersions modified by PDMS were characterized by Fourier transform infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM). The morphology and element compositions of polyurethane films were examined by scanning electron microscopy-energy dispersive spectroscopy analysis (SEM-EDS).FT-IR spectrum showed that the chain of PDMS had been successfully introduced into PU chain. With the same molecular weights of PDMS, the more PDMS were added, the higher the viscosity and the bigger the particle size of dispersions. Furthermore, the water and toluene resistance of PU films became better but the gloss and mechanical properties became poorer with the increase of PDMS contents. When the concentration of PDMS was 9%, the values of GPU viscosity and toluene resistance of GPU films decreased with the molecular weight of PDMSa increasing. The contact angles and elongation of GPU films reached the maximum (98.7°, 279.4%) but the water absorption value reached minimum(15.5%) when the molecular weight of PDMSa is about 2000. With the molecular weight of PDMSb increasing, the viscosity values and particle size of BPU, the water resistance, contact angles and elongation of BPU films increased but gloss and tensile strength decreased. TEM photographs showed that the shape of particle of both GPU and BPU was irregular. SEM images showed both GPU and BPU films had microphase separation. EDS analysis demonstrated that PDMS had surface enrichment. Comparative study on feed order showed that the sample with PDMS added first showed better comprehensive properties.We compared the properties of GPU and BPU and found that GPU had better water and toluene resistance than BPU with the same content of PDMS with similar molecular weight. Polyurethane modified by PDMS with good comprehensive properties can be synthesized in the industrial production by adding 7% PDMSa which molecular weight is about 2000.更多还原