摘要
合成了含双羟基的甲基丙烯酸甘油酯(GM)并将其作为偶联剂用于聚丙烯酸酯(PAC)对水基聚氨酯(PU)的改性.采用核磁共振、红外光谱和气相色谱等对GM进行了表征.分别以该双羟基GM和单羟基的丙烯酸羟乙酯(HEA)与异氰酸酯基(NCO)封端的PU预聚体进行反应以在PU分子链上引入双键,然后再与丙烯酸酯类单体通过自由基聚合制备了丙烯酸酯改性聚氨酯(PU-AC)乳液.反应温度相同时,使用GM时NCO的转化率明显比使用HEA时的高,但PU与PAC的接枝率却明显比使用HEA时的低.改变PU预聚体与任何一个偶联剂的反应温度时,反应温度的升高都能使NCO的转化率及此后与AC发生接枝的PU明显增加.使用HEA作偶联剂时的乳胶粒粒径稍有增大,基本不受前期偶联剂与PU反应时反应温度的影响,所得末端含双键PU的分子量无明显变化;但使用GM作偶联剂时,随着GM与PU预聚体反应时温度的升高,复合乳液乳胶粒径迅速增大,粒径分布明显变宽.所得含双键PU的分子量随GM用量的增加有2种情况:当体系中羟基与异氰酸酯基摩尔比,即n(OH)/n(NCO)<1时,含双键PU的分子量随GM的增加而上升;当n(OH)/n(NCO)>1时继续增加GM用量反而使PU分子量降低.固定反应温度在75℃,当n(OH)/n(NCO)<1时,无论使用哪个偶联剂,其用量的增加都能使最终乳液聚合物中PU的接枝率逐增加,但n(OH)/n(NCO)>1后对PU接枝率的影响不明显.
Dihydroxyl containing glyceryl methacrylate（GM）,a coupling agent in polyurethane（PU） modification by acrylic polymers（PAC）,was first synthesized through hydrolysis of glycidyl methacrylate,and its structure was confirmed through 13 C-NMR,FTIR and gas chromatography.GM was then reacted with isocyanate terminated PU prepolymers to input vinyl group with objective to conduct graft-polymerization with acrylics in a subsequent step,and to get acrylic modified polyurethane（PU-AC） latexes.Hydroxyethyl acrylate（HEA） was also used in the same way as GMa,nd the results were compared.The results showed that,under the same reaction temperature for PU with the 2 coupling agents,higher NCO conversion combined with a lower grafting of PU to PAC was observed with GM.As regard to the influence of temperature in the reaction of PU with the coupling agentsr,esults indicated that both NCO conversion and PU grafted to PAC in the final latex polymers were increased with increasing the reaction temperature,regardless of using GM or HEA.The molecular weight of the PU prepolymers remained nearly constant upon reaction of PU with HEA,and a slight increase in the particle size in the final PU-AC latex was detected.However,with GMt,he impact of this reaction temperature on the PU prepolymers was different from that with HEA.With GM,when OH /NCO molar ratio was inferior to 1t,he molecular weight of the vinyl attached PU increased,and a decrease was detected when OH /NCO was superior to 1.For both coupling agentst,he grafting of PU to PAC was enhanced with more coupling agent when OH /NCO was inferior to 1,and this enhancement was nearly disappeared when OH /NCO molar ration was superior to 1.
出处
《高分子学报》
SCIE
CAS
CSCD
北大核心
2011年第4期409-420,共12页
Acta Polymerica Sinica
基金
国家自然科学基金(基金号20874040)资助项目
