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摘要：在0-100℃溫度范圍內(nèi)，在不同反應(yīng)溫度下進(jìn)行磺酸甜菜堿類單體，N，N-二甲基-N-甲基丙烯酰氧乙基-N-丙基磺酸銨(DMAPS)和N，N-二甲基-N-甲基丙烯酰氧乙基-N-丁基磺酸銨(DMABS)，普通自由基聚合反應(yīng)，采用質(zhì)子核磁共振(1H NMR)測(cè)得聚合物的立構(gòu)規(guī)整度，結(jié)果表明：聚合物的間同立構(gòu)規(guī)整度隨反應(yīng)溫度的降低而增大。產(chǎn)生這一現(xiàn)象的原因是，磺酸甜菜堿類單體是兩性離子單體，由于電荷作用和單體側(cè)基的位阻效應(yīng)，使得在聚合過(guò)程中更容易形成間同立構(gòu)。根據(jù)Bernoulli模型估算出全同和間同增長(zhǎng)的活化焓差ΔH為13.72kJ/mol和活化熵差ΔS為33.66J/(K·mol)，這說(shuō)明生成間同立構(gòu)是熱力學(xué)有利的。在反應(yīng)溫度不變的情況下，在不同的NaCl濃度的溶液中進(jìn)行磺酸甜菜堿類單體普通自由基聚合，質(zhì)子核磁共振(1H NMR)結(jié)果表明：當(dāng)反應(yīng)溫度不變時(shí)，反應(yīng)液中單價(jià)態(tài)離子濃度越低，聚合物間同立構(gòu)規(guī)整度越高。 關(guān)鍵詞：兩性離子單體 立構(gòu)規(guī)整度 磺酸甜菜堿單體 核磁共振氫譜
Abstract：In the temperature range of 0-100℃, sulfobetaine monomers, N,N-dimethyl-N-(methacryloyloxy) ethyl ammonium propyl sulfonate(DMAPS) and N,N-dimethyl-N-(methacryloyloxy) ethyl ammonium butane sulfonate(DMABS), carried out free radical polymerization reaction under different reaction temperatures. Proton nuclear magnetic resonance (1H NMR) measured stereoregularity of polymers, results show that: syndiotactic stereoregularity of polymers with decreasing reaction temperature with increasing. The reason for this phenomenon is, sulfo-betaine monomers are zwitterionic monomers, due to the bulky hindrance and electrostatic interaction, resulting in the polymerization process is easier to form syndiotactic. According to the Bernoulli model, to estimate isotctic and syndiotactic growth activation enthalpy difference ΔH 13.72kJ/mol and activation entropy difference ΔS 33.66J/(K·mol), which generates syndiotaxy is thermodynamically favorable. In response to temperature unchanged, the free radical polymerization of sulfobetaine monomers in different concentration of NaCl solution. The results of proton nuclear magnetic resonance (1H NMR) show that: when the reaction temperature is constant, the concentration of monovalent ions in the reaction solution is low, the syndiotactic stereoregularity of polymers higher. Key words: zwitterionic monomer, stereoregularity, sulfobetaine monomer, 1H NMR
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