丙烯酸/丙烯酸甲酯无规共聚物的性质研究及其表征

本研究以丙烯酸(AA)、丙烯酸甲酯(MA)为共聚单体,以过硫酸铵和亚硫酸氢钠为氧化还原体系引发剂,异丙醇为链转移剂,以水为溶剂,采用溶液聚合方法合成了P(AA-MA)无规共聚物。采用表面张力仪、热分析仪对共聚物的表面张力和热力学性质进行分析,利用红外光谱、透射电子显微镜对共聚物的结构和形貌进行了表征。     

丙烯酸/丙烯酸甲酯共聚物聚合工艺研究及其表征

以丙烯酸(AA)、丙烯酸甲酯(MA)为共聚单体,以过硫酸铵和亚硫酸氢钠为氧化还原体系引发剂,异丙醇为链转移剂,以水为溶剂,采用溶液聚合方法,合成P(AA-MA)共聚物,利用红外光谱对合成的共聚物结构和组成进行表征,研究了各因素对共聚物的特性粘数的影响程度,确定了最佳聚合条件为:单体比例为8∶1,加料时间0.5 h,聚合温度80℃,聚合时间2.5 h,过硫酸铵用量6%,亚硫酸氢钠用量2%,异丙醇100%(以单体质量计)。     

MA/AA/SSS三元共聚物的制备及其阻垢性能研究

以马来酸酐(MA)、丙烯酸(AA)、对苯乙烯磺酸钠(SSS)为单体,水作溶剂,过硫酸铵为引发剂,异丙醇为链转移剂,通过自由基聚合法制备了具有阻垢性能MA/AA/SSS三元共聚物。采用红外光谱法(FTIR)和热重分析(TG)等物理手段对聚合物化学结构及热稳定性进行表征。以共聚物的阻垢率为考察指标,系统研究了单体摩尔比、反应温度、反应时间、引发剂用量、链转移剂用量等因素对其阻垢性能的影响。研究结果表明,当MA、AA、SSS的摩尔比为4∶2∶1,反应温度为80℃,反应时间为4 h,引发剂用量为单体总质量的10%,链转移剂用量为单体总质量9%时,共聚物对Ca CO_3阻垢率可达85.6%。     

链转移剂2-巯基乙醇对AM/AA共聚反应的影响

以AM和AA为原料，过硫酸铵和亚硫酸氢钠氧化还原体系为引发剂，在链转移剂的作用下，采用水溶液聚合的工艺路线，合成了低相对分子质量的AM／AA共聚物。比较了不同链转移剂的作用效果；研究了2-巯基乙醇作为链转移剂对聚合过程和共聚物相对分子质量的影响。结果表明：在共聚物相对分子质量较低时，可以较大幅度提高聚合单体的浓度，聚合能平稳进行。     

耐高温泥浆降滤失剂的制备及评价

随着石油勘探开发逐渐向深部地层和海上发展,钻探地层日趋复杂,对钻井液的高温稳定性提出了更高的要求,加快了耐温型泥浆降滤失剂的研究和开发。本文以2-丙烯酰胺基-2-甲基丙磺酸(AMPS)、丙烯酰胺(AM)、丙烯酸(AA)和烯丙基磺酸钠(AS)为单体[1],采用过硫酸铵/亚硫酸氢钠氧化还原体系,通过水溶液聚合法合成了耐温型泥浆降滤失剂M,并在淡水泥浆、4%盐水泥浆中对合成共聚物M的降滤失性能进行了室内评价,结果表明产物具有良好的耐温和降滤失能力。     

一种水溶性AM/AA/AI共聚物的合成及性能研究

由丙烯酰胺(AM)、丙烯酸(AA)、烯丙基咪唑(AI)在过硫酸铵-亚硫酸氢钠氧化还原引发体系下合成了一种新型的AM/AA/AI水溶性三元共聚物。确立了最佳反应条件:AM∶AA=2∶1(wt%),单体AI的用量为0.1wt%(占单体总质量),引发剂用量0.45wt%,反应温度40℃;并通过红外光谱分析确认了AM/AA/AI三元共聚物结构。当NaCl,CaCl2浓度分别在12000 mg/L,1400 mg/L时,AM/AA/AI三元共聚物的粘度保留率分别约为41%,30%。     

马来酸酐-丙烯酸二元共聚物的合成研究

以马来酸酐(MA)和丙烯酸(AA)为原料,采用活泼单体滴加的方式,通过水溶液自由基共聚合反应制备了MA/AA二元共聚物(PMAAA)。采用FTIR对产物的结构进行了表征,通过正交实验和单因素实验对影响聚合反应的因素进行了考察和优化。在n(MA)∶n(AA)=1∶2,聚合温度85℃,AA滴加时间为1.5h,聚合时间2h,引发剂过硫酸铵用量为总单体质量的8%时,MA的转化率为72.78%。     

乳液聚合法合成高相对分子质量聚醋酸乙烯酯的研究

本文采用过硫酸铵/亚硫酸氢钠氧化还原体系低温引发醋酸乙烯酯乳液聚合,分别讨论了聚合温度、单体用量、十二烷基硫酸钠(SDS)用量、过硫酸铵用量、亚硫酸氢钠用量等因素对聚醋酸乙烯酯粘均相对分子质量的影响。通过调节单体浓度、SDS浓度、过硫酸铵浓度、亚硫酸氢钠浓度和聚合温度,合成出高相对分子质量的聚醋酸乙烯酯,用GPC法对其进行表征,粘均相对分子质量为1.07×106,相对分子质量分布为2.75。     

AA/HPA/SVS三元共聚物阻垢剂的合成及其性能研究

以丙烯酸(AA),丙烯酸羟丙酯(HPA)和乙烯基磺酸钠(SVS)为单体,过硫酸铵为引发剂,异丙醇为链转移剂,在水相中进行自由基聚合反应,合成了AA/HPA/SVS水溶性三元共聚物阻垢剂.系统考察了聚合工艺条件对该共聚物阻垢效果的影响,并对其阻垢分散性能进行了初步评价.结果表明,n(AA):n(HPA):n(SVS)为3:1:1,引发剂用量为14%,链转移剂用量为10%,反应温度为90℃,反应时间为2.5 h时,合成的共聚物阻垢性能最佳,在用量为16 mg·L-1时对碳酸钙和磷酸钙的阻垢率均能达到90%以上,并且具有较好的钙容忍度和分散氧化铁性能.     

衣康酸/苯乙烯磺酸/丙烯酸共聚物阻垢剂的合成研究

以衣康酸(IA)、苯乙烯磺酸(SSA)和丙烯酸(AA)为单体,过硫酸铵为引发剂,异丙醇为链转移剂,在水相中合成了IA/SSA/AA共聚物阻垢剂.通过正交试验确立了最佳合成工艺条件:单体质量比m(IA):m(SSA):m(AA)=2:1:4,引发剂与总单体的质量比为4.5%,链转移剂与总单体质量比为9.5%,在95℃下反应2 h.当IA/SSA/AA共聚物的极限黏数为5.5～6.0 mL/g,实验水中Ca2 的质量浓度为1.6g/L,阻垢剂投加质量浓度为10 mg/L时,共聚物阻CaCO3垢的阻垢率高达91.9%,特别适用于高矿化度的工业循环冷却水和油田回注水.     

Determination of surface basic groups in cationic polystyrene latexes

Basic groups chemically bound to the surface of particles (surface basic groups) in cationic polystyrene latexes prepared by using 2,2′-azobis(2-amidinopropane) hydrochloride as initiator (initiator process) or by copolymerizing dialky aminoethyl methacrylates (copolymerization process) have been determined. It is clarified that in the initiator process amidino endgroups of polymers are effectively localized on the surface of particles and the latex is sufficiently stabilized with surface amidino groups. In the copolymerization process, the neutralized form of dialkylaminoethyl methacrylates is preferably localized on the surface of particles and the latex is sufficiently stabilized with surface amino groups. A particle formation process in both cases has been proposed.     

Surface structure and adhesive properties of biaxially oriented polypropylene film grafted with poly(acrylic amide) using corona discharge

Corona discharge was explored as a means of forming chemically active sites on the surface of biaxially oriented polypropylene (BOPP) film. The active species formed in air was used to induce graft copolymerization of acrylic amide (AAM) in aqueous solution. The surface structure, hydrophilicity and adhesion of the grafted BOPP film were characterized by the extent of grafting, electron spectroscopy for chemical analysis (ESCA), scanning electron microscopy (SEM), peel strength and contact angle measurements. Surface graft‐copolymerization of AAM onto BOPP film by corona discharge in air can be carried out with high efficiency. With increasing copolymerization time, the degree of grafting of AAM onto BOPP increases. The degree of grafting achieved a relatively high value of 2.13 wt% for the conditions of 1 min corona discharge and a copolymerization reaction time of 2.5 hr in 20% AAM aqueous solution at 70°C. After corona discharge grafting, the contact angle of water on the BOPP film decreased and the peel strength increased compared with those for ungrafted BOPP film. The hydrophilicity and adhesion of BOPP were improved by surface graft copolymerization with AAM induced by corona discharge.     

单分散St-PEG200DMA交联共聚微球的合成

以苯乙烯（St）为主单体,PEG200DMA(polyethelyene glycol 200-dimethacrylae)为交联剂,偶氮二异丁腈（AIBN）为引发剂,聚乙烯吡咯烷酮（PVP）为稳定剂,利用一次投料分散聚合的方法合成了交联的St-PEG200DMA共聚微球.实验发现,共聚单体PEG200DMA的投料量对微球的粒径影响不大,但对其形态影响显著.当交联剂的投料量到单体的2.5％时,得到了单分散性好的“花瓣状”微球,这种特异的表面形貌是由交联剂的链段结构决定的.     

Preparation of cationic polystyrene latexes in the absence of emulsifiers

Preparation of cationic polystyrene latexes has been investigated in the absence of emulsifiers. It is clarified that a stable latex can be obtained by using 2,2′-azobis(2-amidinopropane) hydrochloride as initiator (initiator process). The latex seems to be stabilized with the fragments of the initiator chemically bound to the surface of particles. More stable latexes can be obtained by copolymerizing cationic monomers such as dialkyl aminoethyl methacrylates (copolymerization process). The stability of these latexes may predominantly be attributed to cationic monomers chemically bound to the surface of particles. Stable latexes with high solids content can be obtained by using the two-step polymerization technique in the copolymerization process. The particle formation process in the initiator process and the copolymerization process is discussed.     

表面接枝改性木粉及其在PVC基木塑复合材料中的应用

以硝酸铈铵为引发剂引发丙烯酸丁酯(BA)在木粉表面的接枝聚合反应.探查了其表面改性的最佳工艺;接触角数据表明木粉经接枝共聚后,其表面性质已经由亲水变为疏水;将该改性木粉填充PVC后,复合材料的力学性能得到大幅度提高,其中拉伸强度提高了7.9%,而冲击强度则提高了107.5%.     

Surface photografting polymerization of vinyl acetate,maleic anhydride,and their charge‐transfer complex. VIII. Charge‐transfer complex (4)

In view of the complexity of surface photografting polymerization of vinyl acetate/maleic anhydride (VAC/MAH) binary monomer systems, a novel method was adopted in the present article to obtain insight into the relevant grafting copolymerization mechanism. This method includes two steps: semibenzopinacol dormant groups were first introduced onto LDPE film by UV‐irradiation and then thermally reactivated to produce LDPE macromolecular free radicals, which initiated the grafting copolymerization of VAC and MAH. It was demonstrated that, in the first step, the solvent used to introduce benzophenone (BP) to LDPE film largely affected the subsequent grafting copolymerization, which was closely related to the affinity of the solvent toward the substrate. The monomer feed composition had considerable influence on both the grafting and nongrafting copolymerization; however, the maximum copolymerization rates did not appear in the polymerization system with [VAC]/[MAH] being 1 : 1, but, in the system with a bit more VAC than MAH, as the total monomer concentration was raised, the maximum copolymerization rates tended to appear in the system with [VAC] equal to [MAH]. The relationship between the total copolymerization rate (RP) and monomer concentration was determined to be LnRP ∝ [VAC + MAH]^1.83. All of these results indicated that both charge transfer (CT) complex formed by VAC and MAH and free monomers took part in grafting copolymerization. This feature differentiated the surface grafting copolymerization of VAC/MAH from the well‐studied thermally induced alternating copolymerization of VAC/MAH. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

淀粉丙烯酰胺表面控制反应机理及接枝产物结构表征

以木薯淀粉和丙烯酰胺为主要原料,采用反相乳液聚合方法合成淀粉丙烯酰胺接枝共聚物,并通过红外光谱、电镜扫描、X射线衍射、热分析等手段对接枝共聚产物进行结构分析和聚合机理探讨。实验结果显示,淀粉与丙烯酰胺的反应主要发生在淀粉团粒表面,符合表面控制反应机理;接枝共聚物中含有淀粉和丙烯酰胺成分;共聚反应改变了原淀粉的聚集形态,接枝产物基本上为无定形的聚集态结构;但对淀粉的热稳定性影响不显著。     

Modification of poly(tetrafluoroethylene) and gold surfaces by thermal graft copolymerization for adhesion improvement

The adhesion between a poly(tetrafluoroethylene) (PTFE) film and a gold substrate was achieved by surface graft copolymerization of glycidyl methacrylate (GMA) on an argon plasma-pretreated PTFE film at elevated temperature with simultaneous lamination to a surface-modified gold substrate. The plasma pretreatment introduces peroxides which are thermally degraded into radicals to initiate the graft copolymerization of GMA on the PTFE surface. The gold surface, on the other hand, was first pretreated with 3-mercaptopropionic acid (MPA), 3-mercaptopropionic acid-2-ethylhexyl ester (MPAEE), or (3-mercaptopropyl)trimethoxysilane (MPTMS) to form self-assembled monolayers (SAMs) and then subjected to Ar plasma treatment. The simultaneous graft copolymerization and lamination of the PTFE film to the gold surface was carried out in the presence of GMA and an amine hardener at an elevated temperature under atmospheric conditions. The modified surfaces and interfaces were characterized by X-ray photoelectron spectroscopy (XPS) and contact angle measurements. The gold/GMA/PTFE assembly exhibited a T-peel adhesion strength above 10 N/cm and the joint delaminated by cohesive failure inside the bulk of the PTFE film. The strong adhesion of the Au/PTFE laminate is the result of concurrent graft copolymerization on both the Ar plasma-pretreated PTFE surface and the SAM of the Au surface to form a covalent network. The network is further strengthened by the crosslinking reaction promoted by the presence of the hardener.     

Radiation‐induced graft copolymerization of MMA monomer onto UHMWPE: Adhesion improvement

Graft copolymerization of methyl methacrylate monomer onto ultra high molecular weight polyethylene (UHMWPE) and acid‐etched UHMWPE was conducted using preirradiation method in air in the presence of a Mohr salt and sulfuric acid to improve adhesion to the bone cement. The grafted samples were characterized by Fourier transform infrared (FTIR) spectroscopy, gravimetric method, goniometry, and interfacial bonding strength measurements. The FTIR results showed the presence of ether, carbonyl, and hydroxyl groups for grafted films. The gravimetric results showed that the chromic acid etching and graft copolymerization had a synergetic effect so, the irradiated, then chromic acid etched at room temperature and grafted sample (Rad etch25) had the highest grafting degree. The interfacial bonding strength between UHMWPE and poly methyl methacrylate bone cement was considerably improved by graft copolymerization and chromic acid etching. The surface morphology was studied by scanning electron microscopy. The substitution of polar groups into the backbone of UHMWPE by chromic acid etching and graft copolymerization changed its contact angles with water and methylene iodide and increased its surface energy, as evidenced by contact angle measurements. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008