以聚醚為主鏈的新型兩親性接枝共聚物的分子設(shè)計、合成及表征

近年來，由于聚合技術(shù)的發(fā)展，特別是可控/“活性”自由基聚合技術(shù)的出現(xiàn)，使得人們能夠設(shè)計合成出各種線形和非線形結(jié)構(gòu)的共聚物。在這些共聚物中，由親水鏈和憎水鏈組成的接枝共聚物，由于它們具有特殊的結(jié)構(gòu)，豐富的自組裝形態(tài)以及在化學(xué)、物理和生物領(lǐng)域中具有廣泛的用途而引起人們的廣泛興趣。但是，就目前的兩親性接枝共聚物而言，其主鏈大部分是由憎水鏈組成的，而支鏈則由親水鏈組成。由親水主鏈和憎水支鏈組成的接枝共聚物，由于其合成的困難，迄今為止很少有文獻(xiàn)報道。本文提出了一個合成該接枝共聚物的新方法，并在實踐中成功地加以了實施。我們的主要結(jié)果如下：
 1. 利用傳統(tǒng)的陰離子聚合技術(shù)，通過二縮三乙二醇與二苯甲基鉀(DPMK)組成的引發(fā)劑體系首先引發(fā)1-乙氧基乙基-2,3-環(huán)氧丙醚（EPEE）均聚或其與環(huán)氧乙烷(EO)共聚，分別得到線形的窄分布的均聚物PEPEE和共聚物poly(EO-co-EPEE)。得到的聚合物用甲酸水解去保護，并在二氧六環(huán)和甲醇的混合溶劑中用氫氧化鉀溶液皂化后，得到了聚合物鏈的側(cè)端掛有羥甲基官能團的線形聚醚linear Polyglycidol (lPG)和poly(EO-co-Gly)。共聚物poly(EO-co-Gly)的羥基與2-溴異丁酰溴進(jìn)行酯化反應(yīng)，得到側(cè)鏈掛有2-溴異丁酸酯基結(jié)構(gòu)的可以用于原子轉(zhuǎn)移自由基聚合(ATRP)聚合體系的大分子引發(fā)劑Poly(EO-co-Gly)ATRP。然后通過ATRP聚合技術(shù)，分別引發(fā)聚合了苯乙烯(St)、丙烯酸甲酯(MA)、丙烯酸叔丁酯(tBA)和甲基丙烯酸-2-(N, N-二甲氨基)乙酯(DMAEMA)等單體，得到了一系列結(jié)構(gòu)明確的以PEO為主鏈的兩親性接枝共聚物：PEO-g-PS、PEO-g-PMA、PEO-g-tBA、和PEO-g-PDMAEMA，并由PEO-g-tBA通過選擇性水解（三氟乙酸）得到雙親水性接枝共聚物PEO-g-PAA。其中，我們對由大分子引發(fā)劑Poly(EO-co-Gly)ATRP引發(fā)苯乙烯和丙烯酸甲酯這兩種單體的ATRP聚合過程進(jìn)行了動力學(xué)研究，結(jié)果證明聚合過程是可控的。在丙烯酸甲酯的聚合過程中，用乙腈作為溶劑時，其聚合反應(yīng)比本體聚合體系有更好的可控性，共聚物產(chǎn)物的分子量分布也更窄，同時沒有均聚物出現(xiàn)。用凝膠滲透色譜(GPC)、核磁共振(1H NMR)、紅外光譜(FT-IR)、基質(zhì)輔助激光解吸附電離飛行時間質(zhì)譜(MALDI-TOF)等手段對中間產(chǎn)物及最終產(chǎn)物進(jìn)行了詳細(xì)地表征，證明了這種合成聚醚(PEO)為主鏈的接枝共聚物的方法是可行的，并且是成功的。
2. 在陰離子共聚EPEE單體和環(huán)氧乙烷(EO)單體的過程中，通過變換引發(fā)劑體系中的醇的結(jié)構(gòu)(由原來的二元醇變成多元醇，如三羥甲基丙烷和季戊四醇)，合成了星形結(jié)構(gòu)的共聚物，通過水解反應(yīng)脫去保護基團后，再與2-溴異丁酰溴反應(yīng)，得到鏈的側(cè)端掛有很多2-溴異丁酸酯基的星形大分子引發(fā)劑，通過ATRP聚合機理引發(fā)苯乙烯聚合得到PEO為主鏈，PS為側(cè)鏈的星形－接枝共聚物。用凝膠滲透色譜(GPC)、核磁共振(1H NMR)、紅外光譜(FT-IR)、基質(zhì)輔助激光解吸附電離飛行時間質(zhì)譜(MALDI-TOF)等手段對中間產(chǎn)物及最終產(chǎn)物進(jìn)行了詳細(xì)地表征，證明了這種合成聚醚(PEO)為主鏈的星形－接枝共聚物的方法是可行的，并且是成功的。
關(guān)鍵詞：接枝共聚物、星形－接枝，縮水甘油醚、1-乙氧基乙基-2,3-環(huán)氧丙醚、聚苯乙烯、聚丙烯酸甲酯、聚丙烯酸叔丁酯、聚甲基丙烯酸-2-(N,N-二甲基)乙酯、聚丙烯酸

Abstract
Molecular Design, Synthesis and Characterization of Novel Graft Copolymers with Polyether (PEO) as Main Chain
Recently, various of linear and non-linear copolymers were designed and prepared owing to development of synthetic technology, especially in the field of the controlled / “l(fā)iving” polymerization. Amphiphilic graft copolymers containing dydrophilic and hydrophobic chains have received much attention due to their unique structure, many morphologies in solution as well as their potential applications in chemistry, physics, biology, and so on. However, most of these amphiphilic copolymers are composed of hydrophobic main chain and hydrophilic side chains. The inversed architecture graft copolymers with hydrophilic main chain and hydrophobic side chains are scarcely reported because of the difficulties of synthesis. Here, an efficient and universal method is introduced to synthesize the well-defined graft copolymer, three-arm star and four-arm star graft copolymers of PEO as main chain. The essential work completed by us shows as follows:
1. A novel type of well-defined graft copolymer of poly(ethylene oxide) as main chain is successfully prepared by combination of anionic and atom transfer radical polymerization (ATRP). The glycidol is protected by ethyl vinyl ether first to form 2,3-epoxypropyl-1-ethoxyethyl ether (EPEE), then copolymerized with EO by initiation with the mixture of diphenylmethylpotassium and triethylene glycol to give the well-defined poly(EO-co-EPEE). The latter is hydrolyzed in the acidic conditions, then the recovered copolymer of EO and glycidol (Gly) with multi pending hydroxyls [(poly(EO-co-Gly)] is esterified with 2-bromoisobutyryl bromide to produce the ATRP macroinitiator with multi pending bromoisobutyryl groups [poly(EO-co-Gly)(ATRP)]. Subsequently, the latter initiates the polymerization of styrene (St), methacrylate (MA), tert-butyl acrylate (tBA) and 2-(dimethylamino)ethyl methacrylate (DMAEMA) respectively to form the corresponding amphiphilic graft copolymer PEO-g-PS, PEO-g-PMA, PEO-g-PtBA and PEO-g-PDMAEMA. The double hydrophilic graft copolymer PEO-g-PAA is acquired by the hydrolysis of the amphiphilic graft copolymer PEO-g-PtBA. The polymerization kinetic of styrene and methacrylate initiated by poly(EO-co-Gly)(ATRP) are investigated respectively and found that both are well controlled. The object products and intermediates are characterized by 1H NMR, MOLDI-TOF-MS, IR and GPC in detail. It is proved that this route suggested by us to prepare the graft copolymers with PEO as main chain copolymer is successful.
2. A novel type of star-graft copolymer with poly(ethylene oxide) as main chain is successfully prepared by combination of anionic and atom transfer radical polymerization (ATRP). Anionic copolymerized 2,3-epoxypropyl-1-ethoxyethyl ether (EPEE) then with EO by initiation of mixture of diphenylmethylpotassium and polyol [1,1,1-tris(hydroxymethyl)propane (TMP) or pentaerythritol] to give the well-defined three-arm star poly(EO-co-EPEE) and four-arm star poly(EO-co-EPEE). Both star copolymer precursors are hydrolyzed in the acidic conditions, then the corresponding recovered star copolymers of EO and glycidol (Gly) with multi pending hydroxyls [three-arm star poly(EO-co-Gly) and four-arm star poly(EO-co-Gly)] are esterified with 2-bromoisobutyryl bromide to produce the ATRP macroinitiator with multi pending bromoisobutyryl groups [three-arm star poly(EO-co-Gly)(ATRP) and four-arm star poly(EO-co-Gly)(ATRP)].Then the latter initiates the polymerization of styrene (St) to form the corresponding amphiphilic three-arm star PEO-g-PS and four-arm PEO-g-PS. The object products and intermediates are characterized by 1H NMR, MOLDI-TOF-MS, IR and GPC in detail. It is proved that this method to synthesize the graft copolymers with PEO as main chain copolymer is successful.
Key  words: graft copolymer, star-garft, glycidol, 2,3-epoxypropyl-1-ethoxyethyl ether (EPEE)，polystyrene(PS), polymethacrylate (PMA), poly( tert-butyl acrylate) (PtBA), poly[2-(dimethylamino) ethyl methacrylate] (PDMAEMA), poly(acrylic acid)