纳米粒子表面接枝聚醚高分子刷及其对聚氨酯微观结构和性能的影响

发布时间：2018-01-10 04:04

本文关键词：纳米粒子表面接枝聚醚高分子刷及其对聚氨酯微观结构和性能的影响　出处：《西南科技大学》2017年硕士论文　论文类型：学位论文

更多相关文章： 聚氨酯 A200 碳纳米管 SiO_2 接枝性能

【摘要】：聚氨酯(PU)是一类以氨基甲酸酯为基本重复单元的高分子材料,由多异氰酸酯与多元醇,在催化剂及助剂存在下反应而成。由于原材料品种多样及分子结构可调等特点,广泛应用在泡沫塑料、弹性体、涂料、胶黏剂等行业。通过调控交联密度PU可表现出非常宽的硬度范围,其中应用最多为硬质聚氨酯泡沫(RPUF)和聚氨酯(PU)弹性体。然而,RPUF在弯曲、冲击强度、热稳定性、尺寸稳定性等方面仍有不足;此外,PU弹性体的起始模量低、保持高的弹性很难同时提高其模量,限制了其广泛应用。聚合物/纳米复合材料具有有机、无机、纳米材料的特点,因而具有很广泛的应用。然而,纳米粒子存在比表面大、极易团聚、与聚合物基体相容性差等特点,难以实现对聚合物增强增韧的作用。众所周知,在纳米粒子表面接枝聚合物是最有效的表面修饰方法之一,减小纳米粒子团聚,提高纳米粒子在聚合物基体中的相容性。本文首先采用stober法合成SiO2粒子;然后,引入3-甲基丙基三甲氧基硅烷(GPS)于SiO2表面,并通过开环聚合法(ROP)在接枝了 GPS的SiO2表面成功接枝聚环氧丙烷(PPO)高分子刷;最后研究反应条件(温度、时间、单体添加量)对SiO2表面高分子刷接枝量的影响。同时采用ROP法分别在A200、多壁碳纳米管表面接枝聚环氧乙烷(PEO)高分子刷,成功制备PEO-g-A200、PEO-g-MWNT。通过将不同填充量改性前后的A200和MWNT分别填充到RPUF中,制备出 A200/RPUF、PEO-g-A200/RPUF 和 MWNT/RPUF、PEO-g-MWNT/RPUF,并研究不同填充量改性前后的纳米粒子对RPUF的热稳定性、泡孔结构、机械性能等影响。研究发现,对比MWNT/RPUF,PEO-g-MWNT/RPUF具有更好的热机械性能,这可能是因为PEO-g-MWNT与RPUF之间存在强烈的价键作用以及有效的应力传递。此外,添加2.0 wt%的PEO-g-MWNT可以引起RPUF的比强度(σ/ρ)和比模量(E/ρ)分别提高3.57%和15.75%。对比纯RPUF,添加 3.0 wt%PEO-g-MWNT使得RPUF的玻璃化转变温度从11 8 ℃提高到13 5 ℃。当添加0.5 wt%A200时,复合泡沫的压缩强度和Tg都最大,其值分别为19.11 MPa·cm3g-1和136.2 ℃。说明纳米粒子的加入在一定程度上提高了复合泡沫的Tg,填充量过高反而降低了复合泡沫的性能;对于PEO-g-A200/RPUF来说,随着填料PEO-g-A200含量的增加,复合泡沫的Tg逐渐增加,并在填充量为3.0 wt%时,Tg达到最高值为137.2 ℃。通过将不同份数改性前后的MWNT分别填充到PU弹性体中,研究MWNT、PEO-g-MWNT对PU弹性体的热性能和机械性能的影响。随着PEO-g-MWNT含量的增加,Tg向高温移动,说明PEO-g-MWNT与PU之间存在相互作用,阻碍了 PU分子链的运动。随着MWNT添加量的增加(0.1-1.0wt%),PU/MWNT复合材料的拉伸强度先增加后减少;且当MWNT添加量为0.5 wt%时,复合材料的断裂强度和断裂伸长率明显增大,其值分别为36.4 MPa、1085%。填充量高时(1.0wt%),复合材料的起始模量较大,而断裂伸长率最小,可能是MWNT在基体中容易团聚所致。而对于PU/PEO-g-MWNT复合材料来说,当添加量为0.5 wt%时,其断裂强度和断裂伸长率最大,分别为48.3 MPa、1060%。PU/PEO-g-MWNT复合材料的拉伸强度明显优于PU/MWNT,这是因为PEO-g-MWNT与PU弹性体基体之间存在较强的共价键作用,能够在裂缝增长过程中形成桥梁作用,增强韧性的同时提高其强度。
[Abstract]:Polyurethane (PU) is a kind of carbamate as the basic repeating unit of the polymer material, a polyisocyanate and a polyol, as catalyst and additives. Because of the characteristics of varieties of raw materials diversity and molecular structure of adjustable, widely used in plastics, elastomers, coatings, adhesives and other industries. By regulating the crosslinking density of PU can exhibit very wide hardness range, one of the most widely used for rigid polyurethane foam (RPUF) and polyurethane (PU) elastomer. However, RPUF in bending, impact strength, thermal stability, dimensional stability and other aspects are still inadequate; in addition, the initial modulus of PU elastomer is low, high it is very difficult to improve the elastic modulus, limit its application. The polymer / nano composite materials with organic, inorganic, characteristics of nano materials, so it has very wide application. However, nanoparticles are extremely large surface. Easy reunion, the characteristics of the poor compatibility with the polymer matrix, it is difficult to achieve enhanced toughening effect on the polymer grafted on the surface of nanoparticles. As everyone knows, the polymer surface modification is one of the most effective method, to reduce the agglomeration of particles, improve the nanoparticles in the polymer matrix in compatibility. This paper uses the Stober method to synthesize SiO2 particles; then, the introduction of 3- methyl propyl trimethoxysilane (GPS) on the surface of SiO2, and through the ring opening polymerization (ROP) on the surface of SiO2 was successfully grafted onto the surface of GPS grafted poly propylene oxide (PPO) polymer brush; finally studies the reaction conditions (addition of temperature, time, monomer) effect on polymer surface grafting of SiO2 brush at the same time. ROP was used in A200, the surface grafted multi walled carbon nanotubes poly ethylene oxide (PEO) polymer brushes, the successful preparation of PEO-g-A200, PEO-g-MWNT. with different filler content before and after modification of A200 and MW NT was filled into RPUF, prepared by A200/RPUF, PEO-g-A200/RPUF and MWNT/RPUF, PEO-g-MWNT/RPUF, and study the different modified nanoparticles and the thermal stability of RPUF filling volume, pore structure, mechanical properties and so on. The study found that compared to MWNT/RPUF, the thermal mechanical properties of PEO-g-MWNT/ RPUF has better, this may be because between PEO-g-MWNT and RPUF bond strong and effective stress transfer. In addition, the addition of 2 wt% PEO-g-MWNT can cause RPUF strength (O / P) and modulus (E/ P) increased by 3.57% and 15.75% respectively. Compared with the pure RPUF, adding 3 wt%PEO-g-MWNT so that the glass transition temperature of RPUF increased from 118 DEG C up to 135 degrees Celsius. When adding 0.5 wt%A200, and Tg are the maximum compression strength of composite foam, its value is 19.11 MPa cm3g-1 and 136.2 C respectively. The addition of nanoparticles that increase to a certain extent. The Tg composite foam, high filling amount decreases the performance of the composite foam; for PEO-g-A200/RPUF, with the increase of filler content of PEO-g-A200 composite foam Tg increases gradually, and the filling amount is 3 wt%, Tg reached the maximum value of 137.2 degrees. The number of copies of MWNT before and after modification were filled PU elastomer, MWNT, effect of PEO-g-MWNT on thermal and mechanical properties of PU elastomer. With the increase of PEO-g-MWNT content, Tg moved to high temperature, indicating that PEO-g-MWNT interacted with PU, hindered the movement of PU molecular chain. With the increase of MWNT (0.1-1.0wt%), the tensile strength of PU/MWNT the composite increased first and then decreased; and when the amount of MWNT is 0.5 wt%, the breaking strength and breaking elongation of the composites increased obviously, the values were 36.4 MPa, 1085%. (1.0wt%), when the filling amount of composite materials The initial modulus, elongation at break and minimum, may be MWNT easily in the matrix caused by agglomeration of the PU/PEO-g-MWNT composite materials. However, when it was 0.5 wt%, the tensile strength and elongation, respectively 48.3 MPa, tensile strength is obviously higher than that of PU/MWNT 1060%.PU/PEO-g-MWNT composite material, this is because of the existence of covalent bond strong interaction between PEO-g-MWNT and PU elastomer matrix, can form a bridge role in the crack growth process, enhance and improve its strength and toughness.

【学位授予单位】：西南科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O631;TB383.1

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