聚乙二醇支链型丙烯酸树脂复鞣剂的制备及应用性能

用聚乙二醇(PEG400~800)与丙烯酸(AA)进行酯化反应,所得产物聚乙二醇丙烯酸酯(PEGAA)再与AA及甲基丙烯磺酸钠(SMAS)进行共聚反应,制备了聚乙二醇支链型丙烯酸树脂复鞣剂。考察了影响酯化反应及共聚反应的因素,确定酯化反应的条件为:n(PEG)∶n(AA)=1∶1,反应温度110℃,反应时间3 h,酯化率为98%;共聚反应的条件为:n(PEGAA)∶n(AA)∶n(SMAS)=1∶1∶0.2,w(过硫酸铵)=2%,反应温度90℃,反应时间1 h。PEG800支链型丙烯酸树脂的应用效果最好。用FTIR及GPC分别对复鞣剂的结构和相对分子质量进行了表征,最好的复鞣剂质均相对分子质量为26 510,分布系数为6.21。应用结果表明,复鞣革具有丰满、柔软、弹性好、发泡感强、无败色现象等优点。     

一种高性能醚型聚羧酸系减水剂的合成研究

设计四元单体共聚体系,以聚乙二醇异戊烯丙基醚2400(TPEG)、丙烯酸(AA)、甲基丙烯磺酸钠(SMAS)、2-丙烯酰胺基-2-甲基丙磺酸(AMPS)在过硫酸铵(APS)为引发剂存在下共聚,一步法合成高性能的聚羧酸减水剂。经正交实验优选出最佳合成工艺条件如下:AA/TPEG摩尔比为3∶1;AMPS/TPEG摩尔比为0.3∶1,SAS/TPEG摩尔比为0.8∶1,引发剂APS的用量为共聚单体总质量的4%,反应温度为70℃、反应时间为8 h。所合成的聚羧酸减水剂具有优异的减水性能和良好的保坍性能,并能大幅提高所得混凝土拌合物的强度。     

MPEGMA-SMAS-IA三元共聚减水剂的合成及性能

以MPEGMA(马来酸单聚乙二醇单甲醚酯)、SMAS(甲基丙烯磺酸钠)和IA(衣康酸)等为主要原料,通过分子结构设计合成了MPEGMA-SMAS-IA三元共聚的聚羧酸系减水剂,并考察了单体配比、引发剂含量和聚合时间等对其性能的影响。研究结果表明:当n(MPEGMA):n(SMAS):n(IA)=1:0.9:0.2、聚合温度为80℃、聚合时间为5 h和w(引发剂)=10%(相对于单体总质量而言)时,聚羧酸系减水剂的综合性能相对较好;以此作为改性剂,当w(减水剂)=0.33%(相对于水泥质量而言)、水灰比为0.29时,改性水泥净浆的流动度(272 mm)相对最大。     

改性聚乙二醇多磺酸基水处理剂的制备及性能

以过硫酸铵为引发剂,以马来酸酐改性聚乙二醇得到的聚乙二醇酯(PEGMA)、乙烯基磺酸钠(SVS)、丙烯酸(AA)为单体,通过水相自由基共聚反应制备目标共聚物PEGMA-SVS-AA。考察了聚合工艺对其阻碳酸钙垢性能的影响,利用红外光谱对共聚物结构进行表征,得到最佳聚合反应条件为:n(PEGMA)∶n(SVS)∶n(AA)为1∶3∶5,过硫酸铵用量为单体总质量的6%,反应时间2.5 h,控制反应温度为80℃。在该条件下制备的聚合物PEGMA-SVS-AA在模拟工业生产循环冷却水条件下,其阻碳酸钙垢率达到89%。使用XRD和SEM对碳酸钙垢进行了表征,该水处理剂不仅改变了碳酸钙的形貌而且改变了碳酸钙的晶型。     

PEGMMA-MA-IA-SMAS四元共聚减水剂的合成研究

以PEG(聚乙二醇)、MA(马来酸酐)、IA(衣康酸)和SMAS(甲基丙烯磺酸钠)为共聚单体,制备PEGMMA(马来酸聚乙二醇单酯)-MA-IA-SMAS四元共聚减水剂;然后将其用于混合土配方中,并以水泥净浆流动度为考核指标,采用单因素试验法优选合成减水剂的最优方案。结果表明:当减水剂中n(PEG)∶n(MA)∶n(IA)∶n(SMAS)=1∶3.8∶0.5∶1.0、酯化温度为105℃、酯化时间为4 h、w(引发剂)=12.5%(相对于单体总质量而言)、w(催化剂)=4%(相对于PEG和MA总质量而言)、聚合温度为80℃和聚合时间为7.5 h时,合成的减水剂和改性混凝土[w(减水剂)=0.33%]具有相对较好的综合性能;此时,水泥净浆初始流动度(278 mm)相对最大,并且混凝土减水率为28.6%、含气量为2.1%以及28 d压缩强度为49.6 MPa。     

醚型聚羧酸系减水剂的合成及性能研究

烯丙基聚氧乙烯醚、顺酐、丙烯酸、丙烯酰胺为共聚单体,过硫酸铵为引发剂,通过自由基溶液聚合制得四元醚型聚羧酸减水剂。实验表明,最佳工艺条件为n（APEG）：n（MA）：n（AM）：nn（AA）=1：2：1：1．5,引发剂用量为4％．该减水剂在折固掺量为0．14％,水灰比为0129时,水泥的净浆流动度达到336mm,1h后为308mm。放置数月后减水剂稳定性不变。对不同厂家的四种水泥进行了净浆流动度试验,水泥适应性不佳但可调整掺量得到合适流动度。通过FTIR分析,表明MA、AM、AA均接入主链中,APEG接在AM上形成侧链。并依此得出了自制减水剂的分子式。     

聚羧酸减水剂支链密度对水泥水化行为的影响

以聚乙二醇单甲醚((-M)n=750)与丙烯酸为单体,通过酯化反应合成聚乙二醇单甲醚丙烯酸酯大分子单体.用此种大分子单体与烯丙基磺酸钠和不同摩尔比例的丙烯酸在引发剂过硫酸铵的作用下,制备了五种带有聚醚不同支链密度的聚羧酸减水剂.比较了不同支链密度的聚羧酸减水剂对水泥净浆、砂浆性能的影响,以及对水泥浆体水化的影响.结果表明:随着聚氧乙烯基支链密度的增大,水泥净浆流动度增大,分散效果增强,分散保持性增强,且当n(-COOH)∶ n(-OC_2H_4-)为1∶ 1时效果最好;减水率都较高(超过24%),且当n(-COOH)∶ n(-OC_2H_4-)为1∶ 1时高达28.5%.掺加此种比例的减水剂后水泥水化速度提高,水泥砂浆3 d、7 d、28 d抗折、抗压强度明显高于空白样(不掺减水剂的水泥).硬化浆体的SEM和XRD分析也显示聚羧酸减水剂的引入可以加速水泥水化速度,提高水泥砂浆强度.     

Synthesis and characterization of graft copolymers of ethyl acrylate/acrylamide mixtures onto starch

Graft copolymerization of ethyl acrylate/acrylamide onto corn starch using potassium permanganate–citric acid initiation system was investigated. Major factors affecting the polymerization reaction were thoroughly investigated in terms of initiator concentration, monomer concentration, polymerization time, polymerization temperature, and starch/liquor, and the obtained results implied that the polymer yield which were expressed by total monomer conversion, grafting ratio, and grafting efficiency were determined by these factors. The optimum reaction conditions were as follows: starch, 30 g; potassium permanganate (based on weight of starch), 0.1%; citric acid (based on weight of starch), 0.5%; ethyl acrylate, 20%; acrylamide, 0.4 g; time, 3 h; temperature, 40°C; starch/liquor, 1:3. We concluded that the initiator of potassium permanganate–citric acid system could be used as a cheap initiator in manufacturing the starch graft copolymer. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers     

Partially lithiated ternary graft copolymer with enhanced elasticity as aqueous binder for Si anode

Partially lithiated ternary graft copolymers were synthesized through free radical graft polymerization of acrylic acid (AA), lithium acrylate (LiAA) and hydroxyethyl acrylate (HEA) onto polyvinyl alcohol (PVA). With optimized feeding molar ratio of AA/LiAA/HEA (2:1:2), the ternary graft copolymer with partial lithiation shows the best flexibility, elasticity and adhesion strength comparing to PVA-g-PAA and PVA-g-P(AA-HEA) when used as aqueous binder for Si anode. The Si anode using PVA-g-P(AA-LiAA-HEA) with the optimized molar ratio of AA-LiAA-HEA exhibits better cycling stability and rate performance, delivering a capacity of 2265 mAh g⁻¹ with a capacity retention of 82.4% after 200 cycles at 1A g⁻¹. Even at a high current of 10 A g⁻¹, the Si electrode still obtained a high capacity of 1300 mAh g⁻¹.     

聚羧酸系超塑化剂的合成及性能研究

以自制的大分子单体聚乙二醇(PEG,聚合度n=23,35,45)不饱和羧酸单酯(聚乙二醇顺丁烯二酸单酯和聚乙二醇丙烯酸单酯)及其它烯类单体为原料,过硫酸铵为引发剂,经共聚合反应得到了聚羧酸共聚物。研究了大分子单体种类和侧链长度对共聚物分散性、分散稳定性的影响。实验结果表明所合成的聚羧酸共聚物对水泥净浆具有优异的超分散性,在水灰比0.29及掺量0.3%时,水泥净浆流动度可达230 mm。     

含长链聚醚侧基阻垢剂的合成及阻垢性能研究

以丙烯酸(AA)、聚乙二醇单甲醚甲基丙烯酸脂(MPA)为原料,以过硫酸铵-次亚磷酸钠为引发体系,在水溶液中合成了含膦酰基-羧基-醚基的二元共聚物(PAE),通过正交试验法和单因素法选出了最佳合成工艺:单体AA与MPA的质量比为4∶1,引发剂、链转移剂用量分别为总单体质量的4.5%、11%,反应温度为70℃,聚合时间为3h。考察了该共聚物用量对阻垢性能的影响,并与其它阻垢剂的阻碳酸钙性能进行了比较。结果表明,该共聚物具有很好的阻碳酸钙垢、磷酸钙垢和分散氧化铁能力。     

Development and assessment of the advanced graft copolymers obtained from Hibiscus sabdariffa biomass

In this article, the morphological transformation in Hibiscus sabdariffa stem fiber through graft copolymerization with effective ethyl acrylate (EA) and its binary vinyl monomeric mixtures using ceric ammonium nitrate—nitric acid initiator system has been reported. Different reaction parameters such as temperature, time, initiator concentration, monomer concentration, and pH were optimized to obtain the maximum graft yield (117.3%). The optimized reaction parameters were then used to screen the additive effect of EA with n‐butyl acrylate (BA), acrylic acid (AA), and 4‐vinyl pyridine (4‐VP) in binary vinyl monomer mixtures on percentage grafting, properties, and the behavior of the fiber. The graft copolymers were characterized by FTIR, SEM, XRD, TGA, and DTA techniques and evaluated for physico‐chemical changes. With increase in the P_g a significant physico‐chemico‐thermal resistance, miscibility in organic solvents, hydrophobicity were found to increase, whereas crystallinity, crystallinity index, dye‐uptake, and hydrophylicity decreased, however, the cellulose form I remained unchanged. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

含磷丙烯酸-丙烯磺酸钠共聚物阻垢分散剂的合成

以丙烯酸、丙烯磺酸钠和次磷酸钠为原料 ,合成了含磷丙烯酸 -丙烯磺酸钠共聚物阻垢分散剂。最佳工艺条件为 :丙烯酸与丙烯磺酸钠的物质的量比为 6∶1 ,次磷酸钠和引发剂的用量分别为单体总质量的 1 0 %和 1 5% ,反应时间 4h ,反应温度 95℃。阻垢实验结果表明 ,含磷丙烯酸-丙烯磺酸钠共聚物对碳酸钙、硫酸钙和磷酸钙的阻垢率分别为 73 1 %、1 0 0 0 %和 87 9%。     

Graft copolymerization of methyl acrylate onto poly(vinyl alcohol) initiated by potassium diperiodatoargentate(III)

The graft copolymerization of methyl acrylate onto poly(vinyl alcohol) (PVA) using potassium diperiodatoargentate(III) [Ag(III)]–PVA redox system as initiator was studied in an alkaline medium. Some structural features and properties of the graft copolymer were confirmed by Fourier‐transfer infrared spectroscopy, scanning electron microscope, X‐ray diffraction and thermogravimetric analysis. The grafting parameters were determined as a function of concentrations of monomer, initiator, macromolecular backbone (X?_n = 1750, M? = 80 000 g mol^?1), reaction temperature and reaction time. A mechanism based on two single‐electron transfer steps is proposed to explain the formation of radicals and the initiation profile. Other acrylate monomers, such as methyl methacrylate, ethyl acrylate and n‐butyl acrylate, were also used to produce graft copolymerizations. It has been confirmed that grafting occurred to some degree. Thermogravimetric analysis was performed in a study of the moisture resistance of the graft copolymer. Copyright © 2004 Society of Chemical Industry     

聚羧酸系减水剂的合成及流动度研究

以聚乙二醇和甲基丙烯酸为原料,在催化剂作用下,通过酯化合成出甲基丙烯酸聚乙二醇单酯,通过正交试验得到制备大单体的最佳反应条件。并以甲基丙烯酸、甲基丙烯磺酸钠和自制大单体为主要原料合成聚羧酸减水剂,通过正交试验确定了最佳反应条件:在单体摩尔比n(MAA)∶n(MPEGMAA)∶n(SMAS)=3∶1∶1,引发剂用量为7.0%,反应温度为75℃,反应物浓度为25%,反应时间为3.0h的条件下,所得产品可使水泥净浆的流动度达到296mm。产品经红外光谱分析,证明为目标产物。     

马来酸型聚羧酸水泥减水剂的合成及性能

从环氧氯丙烷生产的工业下脚料出发经分馏得到的烯丙基氯与焦亚硫酸钠反应生成了烯丙基磺酸钠。以烯丙基磺酸钠、丙烯酸、马来酸聚乙二醇单酯为原料,过硫酸铵为引发剂合成了减水剂,采用正交实验考查了原料的配比。最佳条件为:烯丙基磺酸钠、丙烯酸、马来酸聚乙二醇单酯的摩尔比为7∶2∶10;引发剂用量3.2%;反应时间5h;聚合温度80℃。在优化条件下初始净浆流动度可达271mm,90min后仍有246mm。     

VAc/BA/AA共聚乳液胶粘剂的制备与性能研究

以醋酸乙烯酯(VAc)为原料、丙烯酸(AA)和丙烯酸丁酯(BA)为改性单体、过硫酸铵(APS)为引发剂、辛基酚聚氧乙烯醚(OP-10)和烷基酚聚氧乙烯醚琥珀酸酯磺酸钠(MS-1)为新型乳化剂体系,采用半连续种子乳液聚合法制备了VAc/BA/AA共聚乳液胶粘剂。研究了引发剂用量、乳化剂配比及用量、单体及种子单体用量对乳液性能的影响,并采用FT-IR对其结构进行表征。研究结果表明,当m(VAc)∶m(BA)∶m(AA)∶m(APS)∶m(OP-10)∶m(MS-1)=83∶14∶3∶0.4∶1.25∶0.25、w(种子单体)=17%(相对于总单体而言)时,乳液的综合性能最佳。     

Copolymerization of norbornene and methyl acrylate catalyzed by Nd(naph)<Subscript>3</Subscript>–Al(i-Bu)<Subscript>3</Subscript>

The copolymerization of norbornene (NB) and methyl acrylate (MA) catalyzed by Nd(naph)₃–Al(i-Bu)₃ and the structure of the copolymers are studied in this article. All polymerization reactions were carried out under nitrogen atmosphere using syringe technique. The copolymers are characterized by IR, ¹H NMR, ¹³C NMR, GPC, and TGA. Norbornene and methyl acrylate are 22.2 and 77.8 mol%, respectively, in the copolymer. The molecular weight distribution is M_w/M_n < 2.0. The molecular weight of copolymer changes with the change of NB/MA in molar ratio. Molecular weight and its distribution of copolymer decrease as molar ratio of NB/MA increases. The copolymerization can be performed in solvents such as aromatic hydrocarbon. The copolymerization can be obtained at room temperature, whereas the copolymer yield increases with increasing reaction temperature. The yield of copolymer changes with the Al/Nd molar ratio with a preferable Al/Nd molar ratio of 30.     

Synthesis and characterization of amphiphilic graft copolymer poly(ethylene oxide)-graft-poly(methyl acrylate)

A novel well-defined amphiphilic graft copolymer of poly(ethylene oxide) as main chain and poly(methyl acrylate) as graft chains is successfully prepared by combination of anionic copolymerization with atom transfer radical polymerization (ATRP). The glycidol is protected by ethyl vinyl ether first, then obtained 2,3-epoxypropyl-1-ethoxyethyl ether (EPEE) is copolymerized with EO by initiation of mixture of diphenylmethyl potassium and triethylene glycol to give the well-defined poly(EO-co-EPEE), the latter is deprotected in the acidic conditions, then the recovered copolymer [(poly(EO-co-Gly)] with multi-pending hydroxyls is esterified with 2-bromoisobutyryl bromide to produce the ATRP macroinitiator with multi-pending activated bromides [poly(EO-co-Gly)_(ATRP)] to initiate the polymerization of methyl acrylate (MA). The object products and intermediates are characterized by NMR, MALDI-TOF-MS, FT-IR, and SEC in detail. In solution polymerization, the molecular weight distribution of the graft copolymers is rather narrow (M_w/M_n < 1.2), and the linear dependence of Ln [M₀]/[M] on time demonstrates that the MA polymerization is well controlled.     

聚羧酸系高效减水剂的制备及其性能研究

以聚乙二醇甲基醚(MPEG)、甲基丙烯酸(MAA)、烯丙基磺酸钠(SAS)和过硫酸铵(APS)等单体为原料合成一种聚羧酸高效减水剂,研究了引发剂、链转移剂、单体等因素对水泥净浆流动度的影响,分析了不同减水剂溶液浓度与表面张力的相互关系;研究表明当引发剂用量为单体质量的5％,链转移剂为0.3％,SAS为15％,MAA/MPEG物质的量比为8时,减水剂对水泥的分散性和保塑性较好,对不同水泥具有良好的适应性.