聚羧酸系高效减水剂合成工艺的优化研究

以甲基烯丙基聚氧乙烯醚(HPEG)和丙烯酸(AA)为单体,以过氧化氢-抗坏血酸(H2 O2-Vc)为氧化还原引发体系,以巯基丙酸(MPA)为链转移剂,共聚合成了HPEGAA型聚羧酸减水剂.研究了合成温度、酸醚比及引发剂用量对聚羧酸减水剂分散性能的影响.结果表明,聚羧酸减水剂的最佳合成工艺为:n(AA):n(HPEG)=...     

新型聚羧酸系高性能陶瓷减水剂的合成及应用

选用丙烯酸、马来酸酐和聚乙二醇单烯丙基醚为聚合单体,采用一步法合成了一种聚羧酸系高性能陶瓷减水剂(CA-100)。比较了CA-100、三聚磷酸钠、水玻璃三种减水剂的应用性能。结果表明,CA-100陶瓷减水剂的解胶性能好,适应范围广。这种新型的陶瓷减水剂具有优异的应用潜力。     

丙烯酰胺—烯丙基磺酸钠共聚物的絮凝性能

丙烯酰胺与含磺酸基单体的共聚物用于提高石油回采率已有不少报道,如乙烯基磺酸、丙烯酸磺丙酯、苯乙烯磺酸、2-丙烯酰胺基-2-甲基丙磺酸和甲基丙烯酸磺乙酯。亦有文献提到用丙烯酰胺与烯丙基磺酸钠共聚物,但缺乏详细报道。国内油田钻井液处理剂中的PAC_(142)和PAC_(143)是丙烯酰胺、烯丙基磺酸钠及其它单体的多元共聚物;日本的钻井液处理剂G-20LL是丙烯酰胺、烯丙基磺酸钠和丙烯酸的三元共聚物。本文报道丙烯酰胺与烯丙基磺酸钠的共聚合及产物的絮凝性能。     

含PEG的双亲性氟硅改性丙烯酸树脂防污涂层的制备及性能

以烯丙基聚乙二醇(APEG)、甲基丙烯酸甲酯(MMA)和丙烯酸丁酯(BA)为共聚物单体合成了含聚乙二醇(PEG)的羟基丙烯酸预聚物(BOH),该预聚物再与α,ω-三乙氧基硅烷封端的聚二甲基硅烷低聚物(TSU)和α,ω-三乙氧基硅烷封端的全氟聚醚低聚物(PFU)通过缩合反应制得含有PEG的氟硅改性丙烯酸交联网络防污涂层.通过核磁共振氢谱(~1H-NMR)、红外光谱(FTIR)对聚合物的结构进行了表征.通过原位纳米测试系统、接触角测试和生物评价等表征方法,探讨了树脂中TSU,PFU和BOH配比对表面能、弹性模量及其生物防污性能的影响.结果表明兼具氟硅低表面能性和PEG抗蛋白吸附性能的交联网络涂层TFS-BOH-B具有好的防污性能,且随着TSU和PFU含量增加,防污性能提高.     

磺酸基改性聚羧酸减水剂的合成及性能研究

对不同分子量的烯丙基聚乙二醇醚(APEG)进行封端改性,制得相应的磺酸基改性的APEG单体(APEGS),并与分子量为2400的甲基烯丙基聚氧乙烯醚TPEG和丙烯酸(AA)、马来酸酐(MA)、乙酸乙烯酯(EVAc)在氧化还原引发体系和链转移剂的作用下,进行水溶液自由基共聚,合成了一种磺酸基改性的聚羧酸减水剂SPCE,并对其性能进行了检测。试验结果表明:磺酸基改性的APEG-700为最佳共聚单体,且共聚体系中n(TPEG)∶n(APEGS)∶n(AA)∶n(MA)∶n(EVAc)的最佳配比为1.0∶0.25∶3.0∶2.0∶1.0,合成的聚羧酸减水剂不仅具有良好的分散性和保坍性,而且与不同水泥和矿物掺合料混凝土的适应性好。     

改进型聚丙烯酸系高效减水剂的合成

根据分子结构设计原理,合成了一种改进型聚丙烯酸系高效减水剂(PC-C),对影响减水剂性能的几个关键因素进行了探讨,并用红外光谱表征了其分子结构。通过正交实验获得了最佳的合成参数:乙烯基磺酸钠(SVS):丙烯酸(AA):丙烯酸聚乙二醇单酯(PEA)=1.5:5:3,过硫酸铵(APS)用量为单体总质量的3%;同时研究了减水剂侧链和掺量对分散性能的影响。结果表明:采用甲氧基聚乙二醇(MPEG)作为接枝侧链合成减水剂的分散能力优于采用聚乙二醇(PEG)合成的减水剂;PC-C低掺量即可发挥高分散性能,分散保持性能随掺量的增加而得以提高。     

氟硅协同改性丙烯酸树脂的合成与防污性能研究

以甲基丙烯酸十二氟庚酯(FMA)、甲基丙烯酸聚二甲基硅氧烷基酯(SMA)、甲基丙烯酸甲酯、丙烯酸正丁酯、甲基丙烯酸正丁酯和丙烯酸乙酯为共聚单体,通过溶液聚合反应合成出侧链含有机氟、有机硅的丙烯酸树脂.通过核磁共振氢谱(1H-NMR)、核磁共振氟谱(19F-NMR)、红外光谱(FTIR)对聚合物的结构进行了表征.通过扫描电镜(SEM)、接触角测试和生物评价等方法,探讨了FMA、SMA含量对树脂涂膜性能的影响.结果表明氟硅改性的丙烯酸树脂比单独含氟或含硅改性的丙烯酸树脂具有更低的表面能,而且氟硅改性的丙烯酸树脂涂膜比商业化的聚硅氧烷涂膜具有更好的防污性能.     

三元无规接枝共聚物的合成及其自组装性能的研究

通过甲基丙烯酸羟乙酯(HEMA)引发ε-己内酯(ε-CL)开环聚合得到带有双键的大分子预聚体甲基丙烯酸羟乙酯-聚己内酯(HEMA-PCL), 该预聚体与N-异丙基丙烯酰胺(NIPAAm)及丙烯酸(AAc)自由基聚合得到一系列含有不同比例组分的三元无规接枝共聚物. 研究了该聚合物的自组装性能. 通过1H NMR, FTIR, 凝胶渗透色谱(GPC)对聚合物进行结构和分子量的表征. 通过TEM, DLS与表面张力等方法表征其纳米粒子情况.     

丙烯酸γ-烷氧基-β-羟丙酯的合成及聚合

合成了几种新的丙烯酸γ-烷氧基-β-羟丙酯类单体及其相应的聚合物,聚丙烯酸和聚甲基丙烯酸 γ-甲氧基-β-羟丙酯[P(MHPA)和 P(MHPMA)水凝胶的平衡吸水量分别为聚甲基丙烯酸β-羟乙酯[P(HEMA)]的7和3倍,P(MHPA)和 P(MHPMA)均具有相当高的吸水性能,这可能是由于在其主链上含有亲水性的γ-甲氧基-β-羟丙基的侧基所致。     

链段相容性对聚酯-聚醚多嵌段共聚物组成均一性的影响

<正> 由结晶型芳族聚酯为硬链段,无定型脂肪族聚醚为软链段的聚酯-聚醚多嵌段共聚物,是一类性能优良的热塑弹性体,本文研究链段相容性对这类聚合物组成均一性的影响,因此,合成了一系列不同链段结构的聚酯-聚醚多嵌段共聚物。 如硬链为聚对苯二甲酸乙二醇酯(PET)和丁二醇酯(PBT);软链段有聚乙二醇醚(PET)、聚丁二醇醚(PTMG)、聚二醇醚(PPG)和四氢呋喃同环氧丙烷的共聚醚二醇     

Conformational and hydrodynamic properties of the homopolymer of 2-deoxy-2-methacrylamido-D-glucose and its copolymers with acrylic acid and methacrylic acid

Hydrodynamic properties of the homologous series of the homopolymer 2-deoxy-2-methacryla-mido-D-glucose and the copolymers of 2-deoxy-2-methacrylamido-D-glucose with unsaturated acids in 0.2 M NaCl are studied via static and dynamic light scattering, viscometry, refractometry, and translational diffusion. The copolymers synthesized via the free-radical copolymerization of 2-deoxy-2-methacrylamido-D-glucose with acrylic acid or methacrylic acid contain ～20 mol % acid units. At this amount of acid units, the equilibrium rigidity of copolymer chains corresponds to that of homopolymer chains. The copolymers are distinguished by the hydrodynamic characteristics of molecules. The copolymer with methacrylic acid is similar to the homopolymer, whereas the copolymer with acrylic acid features substantially different parameters of relationships relating the hydrodynamic characteristics of homologs to their molecular masses.     

Novel temperature‐responsive water‐soluble copolymers based on 2‐hydroxyethylacrylate and vinyl butyl ether and their interactions with poly(carboxylic acids)

Novel water‐soluble amphiphilic copolymers have been synthesized by free radical copolymerization of 2‐hydroxyethylacrylate with vinyl butyl ether. In water these copolymers exhibit lower critical solution temperature, which depends on the content of hydrophobic vinyl butyl ether units. The interaction between these copolymers and poly(acrylic acid) or poly(methacrylic acid) in aqueous solutions results in formation of interpolymer complexes stabilized by hydrogen bonds and hydrophobic interactions. An increase in hydrophobicity of the copolymers leads to the enhancement of their complex formation ability with respect to poly(acrylic acid) and poly(methacrylic acid). Poly(methacrylic acid) forms stronger complexes with the copolymers when compared with poly(acrylic acid). The complexes exhibit dual sensitivity to pH‐ and temperature and this property may be easily adjusted regulating the strength of interaction. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 195–204, 2006     

Effects of cyclodextrin-modified polycarboxylate superplasticizers on the dispersion and hydration properties of cement paste

Abstract

A new series of poly (AA-co-β-CD-A-co-TPEG) (PACDs) copolymers were prepared by the copolymerization of a novel monovinyl β-cyclodextrin monomer (β-CD-A), acrylic acid and isoprenyl oxy polyethylene glycol (TPEG-2400), which could be used as superplasticizers and shown excellent dispersion ability. Therefore, this work mainly investigated the adsorption behavior, dispersing properties as well as hydration behavior of cement pastes. Optical microscopy was employed to describe dispersing performance. X-ray diffraction (XRD) and TGA/DTG were utilized to account for the cement hydration process. We found that the PACDs with β-CD-A exhibited outstanding dispersion ability. In addition, the performances of the PACDs were monitored by evaluating the setting time and fluidity of the cement paste. The results clearly shown that the setting time was longer and slump loss was smaller than that of PACD₀ that without β-CD-A. Therefore, PACDs with the proper content of β-CD pendants had excellent performances due to the steric hindrance of the CD moieties.     

Synthesis and Properties of Hydrophilic Copolymers Containing 5-Fluorouracil,Thymine, or Adenine

Hydrophilic copolymers containing 5-fluorouracil (5-FU), thymine, or adenine were prepared by the free-radical copolymerization of methacryloyl-type monomers containing them with water-soluble vinyl monomers such as acrylic acid, methacrylic acid, vinylpyrroli-done, acrylamide, and 4(5)-vinylimidazole with AIBN as initiator. Complex formation between the copolymers and RNA and between the copolymers having complementary nucleic acid bases in aqueous solution and a DMSO-ethylene glycol was studied by means of UV spectroscopy. These copolymers were found to release the N-hydroxyethyl derivatives of 5-FU, thymine, or adenine by hydrolysis of the ester of the polymer side chain under mild conditions. The effects of the kind of water-soluble comonomer, temperature, pH, and the imidazole group as catalyst on the hydrolysis of the ester are discussed.     

Efficient synthesis of branched poly(acrylic acid) derivatives via postpolymerization modification

The utility of pentafluorophenyl esters for the selective introduction of functional units and branch points in well-defined poly(acrylic acid) (PAA) derivatives is demonstrated using a combination of controlled radical polymerization and postpolymerization modification. Reversible addition-fragmentation chain transfer enables the synthesis of well-defined copolymers—poly(pentafluorophenyl acrylate-co-tert-butyl acrylate)—with the active ester repeat units serving as attachment points for reaction with primary amines, specifically tris(2-(t-butoxycarbonyl)ethyl)methyl amine (Behera's amine). Deprotection using trifluoroacetic acid removes both the backbone and side chain t-butyl esters to give a series of branched PAA derivatives containing novel tricarboxylic acid side chains that are well suited to complexation and multidentate interactions. Surprisingly, the active ester homopolymer is shown to have the highest reactivity with Behera's amine when compared to copolymers with lower incorporation of pentafluorophenyl esters, suggesting an intriguing interplay of neighboring group effects and steric interactions. The ability to tune the efficiency of postpolymerization modification gives a library of PAA derivatives.     

Polymeric amphiphiles with hydrophilic main chain spacers: Studies in monolayers and Langmuir-Blodgett multilayers

A methacrylic lipid was polymerized to form an amphiphilic homopolymer and random copolymers with various levels of acrylic acid comonomers. The behavior of these polymeric lipids was investigated in monolayers at the air-water interface and in Langmuir-Blodgett multilayers on polymer foil supports. The acrylic acid acts as a hydrophilic spacer along the polymer backbone, and improves the ability of the polymer to self-organize into highly ordered monolayers and ultimately LB multilayers. It is shown that the quality and stability of the multilayers increase substantially with the increase in comonomer content.     

Amphiphilic Seven-arm Star Triblock Copolymers with Diverse Morphologies in Aqueous Solution Induced by Crystallization and pH

Well-defined amphiphilic seven-arm star triblock copolymers containing hydrophobic crystalline poly(ε-caprolactone)(PCL) blocks, hydrophobic non-crystalline poly(tert-butyl acrylate)(PtBA) blocks and hydrophilic poly(ethylene glycol)(PEG) blocks were precisely synthesized by a combination of ring-opening polymerization(ROP), atom transfer radical polymerization(ATRP) and “click” reaction. Such star copolymers could self-assemble into “core-shell-corona” micelles and “multi-layer” vesicles depending on the fraction of each block. Meanwhile, the selective hydrolysis of middle PtBA blocks into the poly(acrylic acid)(PAA) blocks allowed the star block copolymers to further change their morphologies of aqueous aggregates in response to pH values.     

Stabilization of water/n‐hexane emulsions by amphiphilic copolymers based on vinyl ethers and their polycomplexes with poly(acrylic acid)

Amphiphilic random copolymers based on vinyl ether of ethylene glycol and vinyl butyl ether as well as their polycomplexes with poly(acrylic acid) were studied as polymeric reagents for the stabilization of water/n‐hexane emulsions. The emulsion stability strongly depended on the content of vinyl butyl ether in the copolymers as well as their concentration in solution. The more hydrophobic copolymers stabilized emulsions more efficiently. An increase in the temperature and the addition of inorganic salts reduced the emulsion lifetime. The formation of interpolymer complexes between the copolymers and poly(acrylic acid) significantly influenced the stability of the emulsions. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2625–2632, 2004     

PSF-g-PAA和PSF-g-PNIPAAm的合成及其共混膜的环境响应性研究

以氯甲基化双酚A型聚砜(PSF-CH2Cl)为大分子引发剂,通过原子转移自由基聚合法(ATRP)合成了以聚砜(PSF)为疏水主链、分别以聚丙烯酸(PAA)和聚(N-异丙基丙烯酰胺)(PNIPAAm)为亲水侧链的两种梳状两亲性共聚物PSF-g-PAA和PSF-g-PNIPAAm.利用1H-NMR和GPC对合成产物进行表征.然后,分别将PSF-g-PAA和PSF-g-PNIPAAm与PSF进行共混,通过浸没沉淀相转化法制备了共混膜.研究发现,引入20 wt%的两亲性共聚物后,PSF-g-PAA/PSF共混膜的水通量在pH=2~6区间发生明显的变化,即膜的水通量显示出典型的pH响应性;而PSF-g-PNIPAAm/PSF共混膜的纯水通量在20~60℃温度区间显示出典型的温度响应性.