【摘要】：過氧化聚合物是單個(gè)大分子鏈內(nèi)含有多個(gè)過氧鍵的一類聚合物,可以分為酸聚過氧化物和乙烯基聚過氧化物,其中乙烯基聚過氧化物具有分解放熱、可自動(dòng)熱分解及自動(dòng)加速等特點(diǎn),�？勺鳛楣腆w燃料和引發(fā)劑等使用。與傳統(tǒng)引發(fā)劑相比,乙烯基聚過氧化物不僅可以引發(fā)聚合反應(yīng)而且還可以合成嵌段、接枝等特殊結(jié)構(gòu)的聚合物。乙烯基聚過氧化物通常由乙烯基單體和氧氣在低溫、常壓條件下共聚而成。采用該方法合成的乙烯基聚過氧化物的分子量和產(chǎn)率都非常低,其分子量只有4000-5000,產(chǎn)率僅為10%左右,再加上低溫引發(fā)聚合(100?)時(shí)過氧化聚合物的引發(fā)效率極低,因此乙烯基聚過氧化物作為引發(fā)劑并未得到廣泛應(yīng)用。但近期的一些研究表明,乙烯基聚過氧化物可能是一種合適的高溫引發(fā)劑,在高溫引發(fā)聚合時(shí)可能有較高的引發(fā)效率,如果乙烯基聚過氧化物的分子量足夠大,那么就可以用乙烯基聚過氧化物作引發(fā)劑通過自由基聚合合成鏈段較長(zhǎng)的嵌段共聚物�；谏鲜鱿敕�,本文首先研究了以甲基丙烯酸甲酯作為乙烯基單體,氧作為共聚單體合成高分子量聚甲基丙烯酸甲酯過氧化物(PMMAP)的合成方法;然后,對(duì)合成的高分子量PMMAP引發(fā)不同烯類單體高溫自由基聚合的引發(fā)能力及引發(fā)聚合后形成的聚合產(chǎn)物的結(jié)構(gòu)與性能進(jìn)行了研究;在此基礎(chǔ)上,利用高分子量PMMAP在選擇性溶劑中原位引發(fā)苯乙烯聚合合成核殼結(jié)構(gòu)PMMA-b-PS嵌段共聚物。通過上述研究最終得出如下結(jié)論:(1)采用高溫自由基聚合在無(wú)引發(fā)劑的條件下可以合成分子量在1.78×104~6.35×104范圍內(nèi)的高分子量聚甲基丙烯酸甲酯過氧化物,合適的聚合溫度為120℃~140℃,氧氣壓力為0.1MPa~0.7MPa。(2)采用高溫自由基聚合合成的高分子量聚甲基丙烯酸甲酯過氧化物在聚合溫度大于110℃時(shí)可以引發(fā)丙烯酸甲酯、丙烯酸羥乙酯及苯乙烯等單體聚合,且聚合溫度越高,聚合速率越大,其引發(fā)聚合的最佳溫度范圍為120℃~150℃。(3)聚甲基丙烯酸甲酯過氧化物引發(fā)聚合時(shí),其合成條件、濃度及聚合溫度都對(duì)聚合反應(yīng)速率有影響。聚合溫度相同時(shí),過氧化聚合物的合成溫度越低,濃度越大,聚合反應(yīng)速率越高,反應(yīng)的轉(zhuǎn)化率越高。(4)聚甲基丙烯酸甲酯過氧化物作引發(fā)劑引發(fā)聚合時(shí)可以合成嵌段長(zhǎng)度可控的嵌段共聚物,嵌段共聚物的比例大于90wt%。嵌段共聚物中PMMA鏈段的長(zhǎng)度可以通過調(diào)節(jié)PMMAP的分子量來進(jìn)行控制。在適當(dāng)?shù)娜軇┲型ㄟ^原位自組裝可以合成粒徑為100nm~800nm的核殼結(jié)構(gòu)PMMA-b-PS嵌段共聚物微球。
[Abstract]:Peroxide polymer is a kind of polymer containing multiple superoxide bonds in a single macromolecular chain, which can be divided into acid polyperoxide and vinyl polyperoxide, in which vinyl polyperoxides have partial liberation fever. It can be used as solid fuel and initiator. Compared with traditional initiators, vinyl peroxide can not only initiate polymerization but also synthesize block, graft and other special structure polymers. Vinyl peroxide is usually copolymerized by vinyl monomer and oxygen at low temperature and atmospheric pressure. The molecular weight and yield of vinyl polyperoxide synthesized by this method are very low, its molecular weight is only 4 000 to 5 000, the yield is only about 10%, and the polymerization initiated at low temperature (100?) Therefore, vinyl peroxide as initiator is not widely used. However, some recent studies have shown that vinyl peroxide may be an appropriate initiator at high temperature and may have a higher initiation efficiency when initiated at high temperature, if the molecular weight of the vinyl peroxide is large enough, The long block copolymers can be synthesized by free radical polymerization with vinyl peroxide as initiator. Based on the above ideas, the synthesis of high molecular weight poly (methyl methacrylate) peroxide (PMMAP) using methyl methacrylate as vinyl monomer and oxygen as monomer was studied. The initiation ability of high molecular weight PMMAP to initiate the high temperature free radical polymerization of different alkenes and the structure and properties of the polymerization products formed after initiation polymerization were studied. Core-shell PMMA-b-PS block copolymers were synthesized by in situ polymerization of styrene with high molecular weight PMMAP in selective solvent. The conclusions are as follows: (1) the high molecular weight polymethyl methacrylate peroxide with molecular weight in the range of 1.78 脳 10 ~ 4 ~ 6.35 脳 10 ~ 4 can be synthesized by high temperature radical polymerization without initiator. The appropriate polymerization temperature is 120 鈩，

本文編號(hào)：2281866