新型阳离子聚丙烯酰胺微粒的研究--含PEO支链阳离子聚丙烯酰胺微粒的合成、助留性能及作用机理

本文采用反相微乳液聚合的方法合成了丙烯酰胺(AM)/丙烯酰氧基乙基三甲基氯化铵(AD-AMQUAT)/聚氧乙烯大单体(PEO-A)/N,N'-亚甲基双丙烯酰胺(Bis)的四元共聚物微粒.研究了该微粒助留剂的结构与性能.这种微粒和纸纤维能够通过离子键和氢键作用显著地增强助留效果.     

N-羟甲基丙烯酰胺的合成及其工艺改进途径

介绍了N 羟甲基丙烯酰胺的基本性能以及合成N 羟甲基丙烯酰胺的丙烯酰胺法、丙烯腈水解法 ;从催化剂的选择及加量、丙烯酰胺与甲醛投料比、反应时间及反应温度、阻聚剂的选用以及甲醛中杂质含量等几个方面综述了合成N 羟甲基丙烯酰胺的工艺改进途径。     

腐植酸钠/聚N-异丙基丙烯酰胺水凝胶的合成及脱色性能研究

探讨了使用低廉而有效的色素吸附剂来吸附亚甲基蓝而减少环境污染。以过硫酸铵为引发剂、N,N′-亚甲基双丙烯酰胺为交联剂、N-异丙基丙烯酰胺单体和腐植酸钠为原料,用溶液聚合交联法合成了温敏腐植酸钠/聚N-异丙基丙烯酰胺(SH/PNIPA)系列水凝胶。用红外光谱分析仪     

反相微乳液聚合制备阳离子聚丙烯酰胺微粒的研究

以丙烯酰氧基乙基三甲基氯化铵、丙烯酰胺、N,N‘-亚甲基双丙烯酰胺为单体采用反相微乳液聚合法制备了阳离子聚丙烯酰胺微粒.研究了Span85和Tween85复合乳化剂的HLB值、乳化剂含量及水油比对乳液稳定性的影响,并对产物的粒径大小及其分布进行了表征.     

三元共聚合成高吸水性树脂的研究

以丙烯酸,丙烯酰胺和2－丙烯酰胺－2－甲基丙磺酸为原料,为硫酸钾为引发剂,N,N－亚甲基双丙烯酰胺（Bis)为交联剂,用水溶液法合成了一系列高吸水性树脂,考察了合成条件对树脂吸水率的影响。     

四元共聚高吸水性树脂的微波辐射合成及性能研究

以过硫酸钾为引发剂,N,N′-亚甲基双丙烯酰胺为交联剂,在没有氮气保护的情况下,采用微波辐射技术合成淀粉/丙烯酸/丙烯酰胺/2-丙烯酰胺基-2-甲基丙磺酸共聚高吸水性树脂,研究了反应条件对树脂吸水倍率的影响,并借助FT-IR、TG和偏光显微镜对其结构、热稳定性及表面形态进行了表征。结果表明,树脂吸水过程符合一级动力学,在优化条件下合成的吸水树脂吸水倍率可达到2 153 g/g,并且具有较好的热稳定性。     

膨润土-高吸水性复合材料复合机理的初探

采用水溶液共聚法制备了膨润土-高吸水性复合材料.通过IR,DSC,TG和生物光学显微镜等测试方法对高吸水性复合材料进行了初步表征,并根据测试分析的结果初步探讨了其复合机理:复合材料是由丙烯酰胺和丙烯酸在引发剂过硫酸铵、交联剂N,N'-亚甲基双丙烯酰胺共同作用下共聚合成,膨润土微粒粘附在高分子网络结构的极性官能团上.     

静置法合成starch/AM/AMPS共聚高吸水树脂

以N,N′-亚甲基双丙烯酰胺(NMBA)为交联剂,通过静置水溶液聚合法制备了淀粉/丙烯酰胺(AM)/2-丙烯酰胺基-2-甲基丙磺酸(AMPS)共聚高吸水树脂。研究了反应条件对树脂吸水性能的影响,所合成的树脂最高吸蒸馏水为1561倍。并通过FTIR、SEM等技术对树脂的分子结构及表面形态进行了表征分析。     

反相微乳液聚合制备阳离子聚丙烯酰胺微粒的研究

以丙烯酰氧基乙基三甲基氯化铵、丙烯酰胺、N,N'-亚甲基双丙烯酰胺为单体采用反相微乳液聚合法制备了阳离子聚丙烯酰胺微粒.研究了Span85和Tween85复合乳化剂的HLB值、乳化剂含量及水油比对乳液稳定性的影响,并对产物的粒径大小及其分布进行了表征.     

三元共聚反相悬浮聚合法合成高吸水性树脂的研究

以丙烯酸、丙烯酰胺、2－丙烯酰胺－2－甲基丙磺酸为原料，过硫酸钾为引发剂，N，N－亚甲基双丙烯酰胺为交联剂，环已烷为连续相，水为分散相，以Span-60为悬浮分散剂，用反相悬浮聚合法合成了一系列高吸水性树脂，考察了合成条件对树脂吸水率的影响。     

Poly(vinyl alcohol)‐controlled synthesis of monodispersed crosslinked poly(methyl methacrylate) microparticles with significantly improved mechanical properties

A facile synthesis concept focusing on the poly(vinyl alcohol) (PVA) concentration induced interfacial energy effects in seed swelling polymerization was realized for the successful fabrication of a series of monodispersed poly(methyl methacrylate) (PMMA) microparticles with four crosslinking agents, 2,2‐bis[(methacryloyloxy)methyl]butyl methacrylate, 1,2‐ethanediyl bis(2‐methylacrylate), 1,3‐divinylbenzene and 1,2‐ethanediyl diacetate. We revealed a special role of PVA in regulating the diffusion of crosslinking agents as well as the swelling degree of latex seeds and, more noticeably, the consequent improved mechanical properties of the crosslinked PMMA microparticles formed. The highest recovery rate obtained from the PMMA microparticles with 0.6 wt% PVA approached 67%, which is higher than or comparable to reported values. This work not only developed a new facile synthesis approach for producing highly uniform tough crosslinked PMMA microparticles for more potential applications but also provided valuable insights into fundamental aspects of seed swelling polymerization. © 2019 Society of Chemical Industry     

Interpolymer complex microparticles based on polymethacrylic acid‐chitosan for oral insulin delivery

In the present study, microparticles composed of polymethacrylic acid‐chitosan (PMAA‐CS) were prepared by a novel interionic gelation method. Free‐radical polymerization of methacrylic acid was carried out in the presence of CS, using a water‐soluble initiator, and application of these microparticles toward oral insulin delivery was evaluated. Microparticles obtained were characterized by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) studies. From SEM studies, it was observed that microparticles had an aggregated morphology with size ～20 μm, while FTIR confirmed the presence of ionic interaction between PMAA and CS chains. Protein loading was done by diffusion filling method, and from in vitro release study, it was observed that insulin‐loaded microparticles displayed a pH depended release profile at alkaline/acidic pH. Microparticles exhibited sustained release of insulin for 3–4 h at neutral pH, and enzyme linked immunosorbent assay (ELISA) proved that encapsulated protein maintained 100% biological activity at neutral pH. Preliminary study suggests that these microparticles can serve as good candidate for oral protein delivery. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 506–512, 2006     

丙烯聚合建模研究:扩散作用的影响

提出了均匀分布多粒模型 (UMGM) ,用于研究单个聚丙烯粒子的增长过程。在不考虑催化剂多活性中心和失活的情况下 ,扩散作用能够在较大范围内解释丙烯聚合过程中分子量分布以及反应速率的变化。分析了扩散系数、催化剂的活性以及催化剂颗粒大小对反应的影响。仿真结果表明 ,扩散作用对高活性催化剂的影响更加显著 ,并且与催化剂粒子的大小有密切关系。本模型能够方便地扩展到多活性中心以及采用更加复杂的微观反应动力学方程 .与其他单粒子模型相比 ,UMGM模型参数物理意义明确 ,计算速度快 ,为工业反应器的建模和优化奠定了基础。     

Influence of the geometric factors of the experimental device used in suspension polymerization on the properties of poly(styrene‐co‐divinylbenzene) microparticles

The prediction of the final particle size for reactive systems such as the reactions of suspension polymerization is a complex matter. Thus, the preparation of very small microparticles is specially challenging, probably because of the coalescence of the polymeric beads taking place during the later stages of the polymerization. In this work, very small gel‐type styrene‐co‐divinylbenzene beads were synthesized by using a previously determined set of experimental synthesis conditions in which the stabilization of the dispersion of the monomeric droplets was ensured, and, under these conditions, the factors related to the geometry of the experimental device were modified to determine their actual effect on the final size of the microparticles. From the experimental results, a very simple and useful model was obtained that was able to predict the final size of the microparticles as a function of the values of the geometric factors of the reactor. This model indicates that the most influential factors in the final size of the microparticles are the liquid depth inside the reactor and the stirrer diameter; thus, an increase in the liquid depth produces larger particles, and, conversely, the particle size decreases when using larger stirrer diameters. Additionally, the model permits the design of polymerization experiments aimed at obtaining microparticles with a diameter smaller than 50 μm. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Formation of monodisperse polyacrylamide particles by dispersion polymerization: particle size and size distribution

Highly monodisperse polyacrylamide microparticles were directly prepared by dispersion polymerization in aqueous alcoholic media initiated by 2,2′‐azobisisobutyronitrile using poly(N‐vinylpyrrolidone) as a steric stabilizer. Monomer conversion was studied dilatometrically and polymer molecular weight was determined viscometrically. The hydrodynamic diameter of polymer particles and its distribution were measured with a dynamic laser light scattering spectrometer. The number of the nuclei produced in the early stage of the polymerization was found to be constant during the remainder of the polymerization. The influences of various polymerization parameters, such as initiator concentration, monomer concentration, stabilizer content, medium polarity, and polymerization temperature on the particle size and size distribution were systematically investigated. Copyright © 2003 Society of Chemical Industry     

(Meth)acrylic Cross‐Linked Polymer Microparticles: Synthesis by Dispersion Polymerization and Particle Characterization

(Meth)acrylic cross‐linked polymer microparticles have been synthesized by dispersion polymerization in organic media. They were produced by radical copolymerization of mono(meth)acrylate monomers with a certain concentration of a diacrylate as cross‐linker, in a mixture of two organic solvents, heptane and propan‐2‐ol. The reactive surfactant (“surfmer”) was a low solubility parameter acrylate monomer, based on an aliphatic ester group (generally C₁₈) or an isobornyl cycle, which gave auto‐dispersing character to the microparticles. By using glycidyl methacrylate in the monomer mixture, oxirane groups were introduced in the particles. The influence of the major synthesis parameters such as solvent composition, monomer composition and concentration, and initiator concentration has been investigated regarding the size and the molar mass of the cross‐linked polymer microparticles. The study was completed with the influence of the nature and the concentration of the surfmer, the concentration of cross‐linking agent and the composition of monomers feed. Stable cross‐linked microparticles ranging from z‐average radius of gyration, R_z = 20 nm to R_z > 60 nm were obtained by varying the synthesis conditions. The smallest microparticles were prepared with a blend of heptane and propan‐2‐ol in the 50/50 ratio by weight. Increasing the surfmer concentration or reducing the monomer concentration in the reaction mixture usually led to smaller microparticles. The longer the aliphatic chain of the surfmer, the smaller the microparticles. Minimum sizes were obtained for cross‐linking agent concentrations between 5 and 7.5 mol‐%, depending on monomers composition. For higher concentrations, macrogelation may occur during the synthesis.     

Synthesis and Evaluation of Uniformly Sized Synephrine-Imprinted Microparticles Prepared by Precipitation Polymerization

Uniformly sized synephrine molecularly imprinted polymer (MIP) microparticles were prepared via precipitation polymerization. The presence of the template, the amount of monomer, crosslinker, and porogenic solvent could affect the size distribution and morphology of the polymers. The pseudo-second-order kinetic model could provide a better correlation for the adsorption than the pseudo-first-order model. The intraparticle diffusion study showed that the sorption involved intraparticle diffusion, but that was not the only rate-controlling step. The equilibrium data better fit the Freundlich model than the Langmuir model. The Scatchard plot of MIPs revealed MIPs had two groups of sites with different affinities. Subsequent recognition selectivity experiments demonstrated preferential structural selectivity for synephrine with respect to other structurally similar compounds (i.e., octopamine and tyramine). Compared with the bulk MIP of SYN, the SYN MIP microparticles in this work had higher adsorption selectivity and capacity due to their smaller particle sizes; moreover, the precipitation polymerization was time-saving due to not using a crash-and-sieve process.     

交联聚合物微粒改性乳液聚合物工艺研究

采用乳液聚合法合成了成膜性很好的聚合物乳液和交联聚合物微粒 (CMP)乳液 ,并将二者共混 ,研究了CMP对聚合物乳液的成膜性及膜性能的影响 ,试验表明CMP对合成的乳液聚合物涂膜有增强作用 ,但其改性工艺仍需改进。对CMP的合成稳定性、成膜性和膜强度以及功能单体对CMP的改性性能也进行了讨论     

Synthesis and structure of the poly(methyl methacrylate) microlatex

Microemulsion polymerization is a new approach for preparing nanosize polymer materials. In this article, a nanosize poly(methyl methacrylate) (PMMA) was prepared by a novel microemulsion polymerization. The kinetics of the polymerization and the effects of the temperature, the monomer, and emulsifier/water ratio on the polymerization were investigated by means of the conversion, the transmittance, and the refractive index measurements. The structure of the obtained PMMA microlatex was studied through transmission electron microscopy (TEM), nuclear magnetic resonance (¹H‐NMR), and differential scanning calorimetry (DSC). The results show that the polymerization exhibits typical kinetic characteristics of a microemulsion polymerization, i.e., there only exists two rate stages: a stage of increasing rate, and a stage of decreasing rate, and no constant rate stage is observed during the polymerization. The obtained PMMA microparticles are very uniform, regular, and small, being about 17–33 nm in the number‐average diameter. The polymer has higher molecular weight (1.71 × 10⁶ viscosity average molecular weight), higher tacticity (51% syndiotacticity), and higher glass transition temperature (127°C), much different from the commercial PMMA. Experimentally, a stable and transparent PMMA microlatex with higher polymer content (30–40 wt %), lower weight ratio of emulsifier to water (E/W ≤ 0.03) and emulsifier to monomer (E/M ≤ 0.05) as well as smaller particle size (d_p < 40 nm), has been prepared, which is very important for the industrialization of the microemulsion polymerization technique. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2839–2844, 2002