【作者】 周翔；

【导师】 张晓梅；

【作者基本信息】 安徽理工大学 ， 应用化学， 2008， 硕士

【摘要】 聚羧酸系超塑化剂是一种能显著改善混凝土和易性和显著减少其拌合水量的新型化学外加剂。它掺量低,减水率高,增强效果显著,坍落度经时损失低,是21世纪高性能混凝土超塑化剂的研究热点。论文对醚类聚羧酸超塑化剂的合成及性能研究进行了以下工作:1.研究了经Willianmson反应制备甲氧基聚氧乙烯基烯丙基醚的合成条件,获得了用不同聚合度聚氧乙烯单甲醚（MPEG,n=17、29、45）合成的不饱和大分子单体（MAPEG）。2.以自制的大分子单体MAPEG（n=17、29、45）、顺酐（MA）及烯丙基磺酸钠（SAS）为共聚合反应单体,过硫酸铵（APS）为引发剂,设计合成了新型醚类聚羧酸超塑化剂（PC）。研究了引发剂用量,聚合反应温度、聚合时间等反应条件对产物分散性的影响;研究了分子结构中侧链长度对分散性和分散稳定性的影响;用正交实验对合成工艺进行了优化。结果表明,在聚合温度88℃左右,聚合7h的条件下:（1）采用聚合度n=17的大分子单体,最佳反应条件为:n_SAS:n_MA:n_MAPEG=2.0:4.0:2.5,引发剂用量为单体总质量的2%,掺加产物的水泥净浆流动度（水灰比W/C=0.29,掺量为0.3%,下同）为235mm。采用聚合度n=29的大分子单体,最佳反应条件为:n_SAS:n_MA:n_MAPEG=1.0:3.5:1.0,引发剂用量为单体总质量的5%,掺加产物的水泥净浆流动度为248mm。采用聚合度n=45的大分子单体,最佳反应条件为:n_SAS:n_MA:n_MAPEG=1.5:3.0:0.5,引发剂用量为单体总质量的7%,掺加产物的水泥净浆流动度为240mm。（2）将一定比例聚合度n=17和n=45的大分子单体混合后参与聚合反应,得到分子结构中含有不同侧链长度的产物,最佳单体配比:n_SAS:n_MA:n_MAPEG（n=17:45）=2.5:3.5:1.0（1:3）,引发剂用量为单体总物质的量的5%,掺加聚合物的水泥净浆流动度达250mm。3.探索微波辐射法合成醚类聚羧酸超塑化剂,研究辐射功率和时间对共聚物结构和性能的影响。在单体配比为n_SAS:n_MA:n_MAPEG（n=29）=1.0:3.5:1.0,引发剂用量为单体总质量5%时,采用辐射功率260W辐射6min,或辐射功率130W辐射8～10min,可获得掺加聚合物的水泥净浆流动度稳定在230mm左右的产物。4.用特性粘数、红外光谱对所合成醚类聚羧酸超塑化剂进行结构表征;测定了产物的表面张力及其在水泥—水体系中ζ电位,观测了硬化水泥和硬化混凝土的微观形貌,测定了掺加产物的新拌混凝土的减水率及硬化混凝土的抗压强度。结果表明:醚类超塑化剂的特性粘数在2.431×10^-2dL·g^-1～3.042×10^-2dL·g^-1范围内时,性能较好。相同实验条件下,微波辐射聚合产物特性粘数较小。分子结构中含有不同侧链长度的PC的ζ电位绝对值增大幅度比单一侧链聚合度PC大;掺加PC（n=17:45）0.3%时,混凝土减水率达23.7%,28天抗压强度比达到163%。更多还原

【Abstract】 Polycarboxylic acids superplasticizers,a kind of new chemical admixtures,can improve the concrete’s workability obviously and reduce the dosage of water.The advantages of low admixing dosage,high water reducing rate,high performance in reinforcing and low slump loss cause them to hit the research area in 21st century.The work on synthesis and performances of ether type polycarboxylic acid superplasticizer was showed as follow.1.Different degree of polymerization macromonomers monomethoxy-poly（ethylene glycol） allyl ether（MAPEG,n=17,29,45） were obtained by Willianmson reaction, and the reacting conditions of preparing MAPEG were studied.2.New type of Polycarboxylic acid superplasticizers（PC） were designed and synthesized by using self-made macromonomers MAPEG（n=17,29,45）,maleic anhydride（MA） and sodium allyl sulphonate（SAS） as copolymerization monomer, ammonium persulfate（APS） as the initiator.The effects of initiator and polyreaction time and temperature on dispersing capability of the superplasticizers were studied, and the length of side-chain on dispersing capability and dispersion stability of the superplasticizers were studied also.The optimum synthesis condition（88℃,7h） by orthogonal experiment was obtained.（1） Superplasticizer with the fluidity on cement slurry 235mm at the dosage of 0.3% and water to cement mass ratio of 0.29 was obtained at the optimum ratio of monomers of n_SAS:n_MA:n_MAPEG=2.0:4.0:2.5（mole ratio） and initiator 2%while using MAPEG（n=17）;and that 248mm at the optimum ratio of monomers of n_SAS:n_MA: n_MAPEG=1.0:3.5:1.0（mole ratio） and initiator 5%while using MAPEG（n=29）;and that 240mm at the optimum ratio of monomers of n_SAS:n_MA:n_MAPEG=1.5:3.0:0.5（mole ratio）and initiator 7%while using MAPEG（n=45）.（2） Superplasticizer with different length side-chain using mixed MAPEG（n=17,n=45） as macromonomer and fluidity on cement slurry 250mm at the dosage of 0.3%and water to cement mass ratio of 0.29 was obtained at the optimum ratio of monomers of n_SAS:n_MA:n_MAPEG（n=17:45）=2.5:3.5:1.0（1:3） and initiator 5%.3.New type of polycarboxylic acid superplasticizer was synthesized under microwave irradiation,and effects of irradiation time and irradiation power on the molecular structure and performances of superplasticizer were studied.Under conditions of n_SAS:n_MA:n_MAPEG（n=29）=1.0:3.5:1.0 and initiator 5%,irradiation power 260W for 6min, or 130W for 8～10min,superplasticizer with the fluidity on cement slurry 230mm at the dosage of 0.3%and water to cement mass ratio of 0.29 was obtained.4.The structures of superplasticizers synthesized were characteristed by intrinsic viscosity and infrared spectrum analysis.The surface tensionin andζpotential in the system of cement-water of superplasticizers were tested,and water reducing rate, solid cement compressive strength after adding superplasticizers are tested also.The hardened cement and concrete morphology sclerosis are observed by SEM.The results showed that the intrinsic viscosities of superplasticizers with good capability may range from 2.431×10^-2dL·g^-1 to 3.042×10^-2dL·g^-1.At the same reacting condition,the vaules of intrinsic viscosity by microwave radiation are less than normal heating.The extent of increasingζabsolute value of superplasticizer with defferent length side-chain is higher than that of with homogeneous length side-chain. The superplasticizer with mixed side-chain（17:45=3:1） got the performances of water reducing ratio of 23.7%and compressive strength ratio of 163%（28d） at the dosage of 0.3%.更多还原