本文關鍵詞：納米粒子表面接枝聚醚高分子刷及其對聚氨酯微觀結構和性能的影響　出處：《西南科技大學》2017年碩士論文　論文類型：學位論文

  更多相關文章： 聚氨酯 A200 碳納米管 SiO_2 接枝 性能

【摘要】：聚氨酯(PU)是一類以氨基甲酸酯為基本重復單元的高分子材料,由多異氰酸酯與多元醇,在催化劑及助劑存在下反應而成。由于原材料品種多樣及分子結構可調等特點,廣泛應用在泡沫塑料、彈性體、涂料、膠黏劑等行業(yè)。通過調控交聯(lián)密度PU可表現(xiàn)出非常寬的硬度范圍,其中應用最多為硬質聚氨酯泡沫(RPUF)和聚氨酯(PU)彈性體。然而,RPUF在彎曲、沖擊強度、熱穩(wěn)定性、尺寸穩(wěn)定性等方面仍有不足;此外,PU彈性體的起始模量低、保持高的彈性很難同時提高其模量,限制了其廣泛應用。聚合物/納米復合材料具有有機、無機、納米材料的特點,因而具有很廣泛的應用。然而,納米粒子存在比表面大、極易團聚、與聚合物基體相容性差等特點,難以實現(xiàn)對聚合物增強增韌的作用。眾所周知,在納米粒子表面接枝聚合物是最有效的表面修飾方法之一,減小納米粒子團聚,提高納米粒子在聚合物基體中的相容性。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,并通過開環(huán)聚合法(ROP)在接枝了 GPS的SiO2表面成功接枝聚環(huán)氧丙烷(PPO)高分子刷;最后研究反應條件(溫度、時間、單體添加量)對SiO2表面高分子刷接枝量的影響。同時采用ROP法分別在A200、多壁碳納米管表面接枝聚環(huán)氧乙烷(PEO)高分子刷,成功制備PEO-g-A200、PEO-g-MWNT。通過將不同填充量改性前后的A200和MWNT分別填充到RPUF中,制備出 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納米粒子對RPUF的熱穩(wěn)定性、泡孔結構、機械性能等影響。研究發(fā)現(xiàn),對比MWNT/RPUF,PEO-g-MWNT/RPUF具有更好的熱機械性能,這可能是因為PEO-g-MWNT與RPUF之間存在強烈的價鍵作用以及有效的應力傳遞。此外,添加2.0 wt%的PEO-g-MWNT可以引起RPUF的比強度(σ/ρ)和比模量(E/ρ)分別提高3.57%和15.75%。對比純RPUF,添加 3.0 wt%PEO-g-MWNT使得RPUF的玻璃化轉變溫度從11 8 ℃提高到13 5 ℃。當添加0.5 wt%A200時,復合泡沫的壓縮強度和Tg都最大,其值分別為19.11 MPa·cm3g-1和136.2 ℃。說明納米粒子的加入在一定程度上提高了復合泡沫的Tg,填充量過高反而降低了復合泡沫的性能;對于PEO-g-A200/RPUF來說,隨著填料PEO-g-A200含量的增加,復合泡沫的Tg逐漸增加,并在填充量為3.0 wt%時,Tg達到最高值為137.2 ℃。通過將不同份數(shù)改性前后的MWNT分別填充到PU彈性體中,研究MWNT、PEO-g-MWNT對PU彈性體的熱性能和機械性能的影響。隨著PEO-g-MWNT含量的增加,Tg向高溫移動,說明PEO-g-MWNT與PU之間存在相互作用,阻礙了 PU分子鏈的運動。隨著MWNT添加量的增加(0.1-1.0wt%),PU/MWNT復合材料的拉伸強度先增加后減少;且當MWNT添加量為0.5 wt%時,復合材料的斷裂強度和斷裂伸長率明顯增大,其值分別為36.4 MPa、1085%。填充量高時(1.0wt%),復合材料的起始模量較大,而斷裂伸長率最小,可能是MWNT在基體中容易團聚所致。而對于PU/PEO-g-MWNT復合材料來說,當添加量為0.5 wt%時,其斷裂強度和斷裂伸長率最大,分別為48.3 MPa、1060%。PU/PEO-g-MWNT復合材料的拉伸強度明顯優(yōu)于PU/MWNT,這是因為PEO-g-MWNT與PU彈性體基體之間存在較強的共價鍵作用,能夠在裂縫增長過程中形成橋梁作用,增強韌性的同時提高其強度。
[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.

【學位授予單位】：西南科技大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：O631;TB383.1

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