【作者】 张宇；

【导师】 吴友平；

【作者基本信息】 北京化工大学 ， 材料科学与工程， 2025， 硕士

【摘要】 热塑性聚氨酯弹性体(TPU)被广泛用于鞋底、非充气轮胎等,但其冰摩擦性能较差。影响材料冰摩擦性能的主要因素有:材料的玻璃化转变温度(T_g)、硬度、表面润湿性、表面粗糙度等。对此,本论文首先选用一系列具有不同T_g、不同极性的橡胶分别与TPU共混,以探究橡胶类型对TPU/橡胶复合材料在干、湿、冰等不同条件下的摩擦性能;其次,以TPU/天然橡胶(NR)复合材料为研究对象,探讨了界面改性对相态结构和冰摩擦性能的影响;在此基础上,选用高硬度的纳米填料,如白炭黑、二氧化钛,及高模量芳纶浆粕,进一步探究了填料类型对TPU/NR复合材料的相态结构、表面粗糙度和表面润湿性的影响,及各因素对冰摩擦性能的影响,研究结果可为设计抗冰滑的TPU复合材料提供参考。具体研究内容如下:(1)选取了T_g不同、极性不同的顺丁橡胶(BR)、环氧天然橡胶(ENR)、高乙烯基溶聚丁苯橡胶(HVSSBR)、丁腈橡胶(NBR),分别与TPU共混,以调控TPU/橡胶复合材料相态结构,探究了橡胶类型对TPU/橡胶复合材料干、湿、冰摩擦性能的影响。结果表明:TPU及TPU/橡胶复合材料的干摩擦系数均达到0.7以上,湿摩擦系数均达到0.3以上,材料的干、湿摩擦性能可满足要求。TPU/NBR冰摩擦性能最优,-10℃和-15℃时,冰摩擦系数提高约20%。与10 phr橡胶共混,TPU的T_g变化小于3℃,邵尔A硬度下降3～5度,变化幅度不大,因而T_g和硬度对冰摩擦性能影响较小;AFM相态结构和T_g结果显示,NBR与TPU相容性最好,其在TPU中分散最均匀。但与TPU相比,TPU/NBR拉伸强度降低29.7%,磨耗体积增至TPU的6倍,耐磨性能明显变差。(2)以TPU/NR复合材料为研究对象,NR用量为20phr,为提高NR与TPU的相容性,分别加入4,4’-二氨基二苯二硫醚(APDS)和双-[γ-(三乙氧基硅)丙基]四硫化物(Si69)两种界面改性剂,探讨了有无界面改性条件下,复合材料硬度、表面润湿性、相态结构对冰摩擦性能的影响。结果表明:三种TPU/NR复合材料较纯TPU的邵尔A硬度降低7～11度,接触面积增加,冰摩擦性能提升。与TPU相比,未改性的TPU/NR冰摩擦系数提高最明显,在-1℃至-15℃提升27%～43%;界面改性(TPU/NR-A、TPU/NR-Si)对冰摩擦性能提升21%～43%,略低于未改性的TPU/NR,主要原因是改性使NR相尺寸减小,不利于提高冰摩擦系数。材料水接触角调控范围有限(<6.2°),Tg偏移小(<1.5℃),因而对冰摩擦性能影响不大。与TPU相比,未改性TPU/NR保持良好力学性能同时耐磨性略有提升。(3)为进一步提高TPU/NR的冰摩擦性能,分别添加高纳米硬度粉末类填料白炭黑、二氧化钛和高模量微米级纤维类芳纶浆粕,以调控材料表面粗糙度,探究不同形貌、尺寸填料对复合材料表面性能及冰摩擦性能的影响。结果表明:白炭黑、二氧化钛增加了材料表面粗糙度,增加摩擦力,提高冰摩擦性能;添加二氧化钛的TPU/NR-T硬度最低,冰摩擦性能最好。与TPU/NR相比,TPU/NR-T在-5℃、-10℃、-15℃时冰摩擦系数分别提升21%、17%、8%。芳纶浆粕使TPU/NR邵尔A硬度增加8度,且未能有效取向导致表面粗糙度减小,未能提高冰摩擦性能。-1℃时因冰面预融化层厚度较厚,材料表面润湿性对冰摩擦性能起主要影响作用,随着材料疏水性增强而降低,添加填料后复合材料疏水性增强,冰摩擦性能下降。当冰温低于-5℃时,预融化层的厚度逐渐变薄,材料表面粗糙度和硬度等是冰摩擦性能的主要影响因素。综合冰摩擦性能、力学性能和耐磨性来看,TPU/NR-T是四种材料中性能最佳的。更多还原

【Abstract】 Thermoplastic polyurethane(TPU)is widely used in shoe soles and non-pneumatic tires,yet its ice friction performance remains suboptimal.Key factors influencing the ice friction properties of materials include the glass transition temperature(T_g),hardness,surface wettability,and surface roughness.To address these challenges,this study first blended TPU with a series of rubbers exhibiting distinct T_g values and polarities to investigate the friction performance of TPU/rubber composites under dry,wet,and icy conditions.Subsequently,TPU/natural rubber(NR)composites were selected to explore the effects of interfacial modification on phase structure and ice friction behavior.Furthermore,high-hardness nanofillers such as silica,titanium dioxide,and aramid pulp were incorporated to systematically analyze the influence of filler types on the phase morphology,surface roughness,wettability,and ice friction performance of TPU/NR composites.The findings provide critical insights for designing ice-resistant TPU composites.The specific research framework is structured as follows:(1)The different T_g and polarity of male-butadiene rubber(BR),epoxy natural rubber(ENR),high vinyl soluble styrene-butadiene rubber(HVSSBR),and nitrile rubber(NBR)were selected and blended with TPU to modulate the phase structure of TPU/rubber composites,and the effect of rubber type on the dry,wet,and icy friction properties of the TPU/rubber composites was investigated.The results showed that the dry friction coefficients of TPU and TPU/rubber composites reached more than 0.7 and the wet friction coefficients reached more than 0.3,and the dry and wet friction properties of the materials could meet the requirements.The ice friction properties of TPU/NBR were optimal,and the ice friction coefficients were increased by about 20%at-10℃and-15℃.Blended with 10 phr rubber,the Tg change of TPU is less than 3℃,and the Shore A hardness decreases by 3～5 degrees,which is not a big change,thus the Tg and hardness have less influence on ice friction performance;the AFM phase structure and Tg results show that NBR has the best compatibility with TPU,and its dispersion is the most homogeneous in TPU.However,compared with TPU,the tensile strength of TPU/NBR decreased by 29.7%,the abrasion volume increased to 6 times that of TPU,and the abrasion resistance deteriorated significantly.(2)TPU/NR composites were used as the research object,and the dosage of NR was 20 phr.In order to improve the compatibility between NR and TPU,two interfacial modifiers,4,4’-diaminodiphenyl disulphide(APDS)and bis-[γ-(triethoxysilyl)propyl]tetrasulphide(Si69)were added respectively,and two interfacial modifiers,with or without the interfacial modification conditions,were investigated.The effects of composite hardness,surface wettability,and phase structure on ice friction performance were investigated with and without interfacial modification.The results showed that the Shore A hardness of the three TPU/NR composites was reduced by 7～11 degrees,the contact area was increased,and the ice friction performance was improved compared with that of pure TPU.Compared with TPU,unmodified TPU/NR showed the most significant improvement in ice friction coefficient,with27%～43%improvement from-1°C to-15°C.Interfacial modifications(TPU/NR-A,TPU/NR-Si)improved ice friction performance by 21%to 43%,which was slightly lower than that of unmodified TPU/NR,mainly because the modification reduced the size of the NR phase,which was not conducive to the improvement of ice friction coefficient.The water contact angle of the material has a limited range of regulation(<6.2°)and the Tg shift is small(<1.5°C),thus it has little effect on the ice friction performance.Compared to TPU,unmodified TPU/NR maintains good mechanical properties with a slight increase in abrasion resistance.(3)To further enhance the ice friction performance of TPU/NR composites,high-nanohardness particulate fillers(silica,titanium dioxide)and high-modulus microfibrous aramid pulp were incorporated to regulate surface roughness,thereby investigating the effects of filler morphology/size on surface properties and their correlations with ice friction behavior.The results showed that silica and titanium dioxide increased the surface roughness of the material,increased the friction force,and improved the ice friction performance;TPU/NR-T with added titanium dioxide had the lowest hardness and the best ice friction performance.Compared with TPU/NR,the ice friction coefficient of TPU/NR-T was improved by 21%,17%,and 8%at-5℃,-10℃,and-15℃,respectively.Aramid pulp increased the Shore A hardness of TPU/NR by 8 degrees and failed to improve the ice friction performance due to the decrease in surface roughness caused by ineffective orientation.-1℃due to the thickness of the ice pre-melting layer is thick,the material surface wettability on the ice friction performance plays a major role in influencing the hydrophobicity of the material to enhance and reduce the addition of fillers after the composite material hydrophobicity enhancement,ice friction performance decreased.When the ice temperature is lower than-5℃,the thickness of the pre-melted layer gradually becomes thinner,and the surface roughness and hardness of the material are the main influencing factors of the ice friction performance.In terms of comprehensive ice friction performance,mechanical properties and wear resistance,TPU/NR-T is the best performance among the four materials.更多还原