本文關(guān)鍵詞：納米粒子表面接枝聚醚高分子刷及其對(duì)聚氨酯微觀結(jié)構(gòu)和性能的影響　出處：《西南科技大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)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(fù)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(yīng)而成。由于原材料品種多樣及分子結(jié)構(gòu)可調(diào)等特點(diǎn),廣泛應(yīng)用在泡沫塑料、彈性體、涂料、膠黏劑等行業(yè)。通過調(diào)控交聯(lián)密度PU可表現(xiàn)出非常寬的硬度范圍,其中應(yīng)用最多為硬質(zhì)聚氨酯泡沫(RPUF)和聚氨酯(PU)彈性體。然而,RPUF在彎曲、沖擊強(qiáng)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(shí)提高其模量,限制了其廣泛應(yīng)用。聚合物/納米復(fù)合材料具有有機(jī)、無機(jī)、納米材料的特點(diǎn),因而具有很廣泛的應(yīng)用。然而,納米粒子存在比表面大、極易團(tuán)聚、與聚合物基體相容性差等特點(diǎn),難以實(shí)現(xiàn)對(duì)聚合物增強(qiáng)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(tuán)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(yīng)條件(溫度、時(shí)間、單體添加量)對(duì)SiO2表面高分子刷接枝量的影響。同時(shí)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(duì)RPUF的熱穩(wěn)定性、泡孔結(jié)構(gòu)、機(jī)械性能等影響。研究發(fā)現(xiàn),對(duì)比MWNT/RPUF,PEO-g-MWNT/RPUF具有更好的熱機(jī)械性能,這可能是因?yàn)镻EO-g-MWNT與RPUF之間存在強(qiáng)烈的價(jià)鍵作用以及有效的應(yīng)力傳遞。此外,添加2.0 wt%的PEO-g-MWNT可以引起RPUF的比強(qiáng)度(σ/ρ)和比模量(E/ρ)分別提高3.57%和15.75%。對(duì)比純RPUF,添加 3.0 wt%PEO-g-MWNT使得RPUF的玻璃化轉(zhuǎn)變溫度從11 8 ℃提高到13 5 ℃。當(dāng)添加0.5 wt%A200時(shí),復(fù)合泡沫的壓縮強(qiáng)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(fù)合泡沫的Tg,填充量過高反而降低了復(fù)合泡沫的性能;對(duì)于PEO-g-A200/RPUF來說,隨著填料PEO-g-A200含量的增加,復(fù)合泡沫的Tg逐漸增加,并在填充量為3.0 wt%時(shí),Tg達(dá)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(duì)PU彈性體的熱性能和機(jī)械性能的影響。隨著PEO-g-MWNT含量的增加,Tg向高溫移動(dòng),說明PEO-g-MWNT與PU之間存在相互作用,阻礙了 PU分子鏈的運(yùn)動(dòng)。隨著MWNT添加量的增加(0.1-1.0wt%),PU/MWNT復(fù)合材料的拉伸強(qiáng)度先增加后減少;且當(dāng)MWNT添加量為0.5 wt%時(shí),復(fù)合材料的斷裂強(qiáng)度和斷裂伸長(zhǎng)率明顯增大,其值分別為36.4 MPa、1085%。填充量高時(shí)(1.0wt%),復(fù)合材料的起始模量較大,而斷裂伸長(zhǎng)率最小,可能是MWNT在基體中容易團(tuán)聚所致。而對(duì)于PU/PEO-g-MWNT復(fù)合材料來說,當(dāng)添加量為0.5 wt%時(shí),其斷裂強(qiáng)度和斷裂伸長(zhǎng)率最大,分別為48.3 MPa、1060%。PU/PEO-g-MWNT復(fù)合材料的拉伸強(qiáng)度明顯優(yōu)于PU/MWNT,這是因?yàn)镻EO-g-MWNT與PU彈性體基體之間存在較強(qiáng)的共價(jià)鍵作用,能夠在裂縫增長(zhǎng)過程中形成橋梁作用,增強(qiáng)韌性的同時(shí)提高其強(qiáng)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(xué)位授予單位】：西南科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：O631;TB383.1

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