苯乙烯-甲基丙烯酸月桂酯-丙烯酸共聚物的合成及性能

以苯乙烯（St）、甲基丙烯酸月桂酯（LMA）、丙烯酸（AA）为单体,过氧化苯甲酸叔丁酯为引发剂,二丙二醇二甲醚为溶剂,采用自由基聚合方法,合成苯乙烯-甲基丙烯酸月桂酯-丙烯酸共聚物。考察了引发剂用量、单体摩尔配比、反应温度对聚合物性能的影响,并用红外光谱、差示扫描量热仪、凝胶色谱等对共聚物进行表征,结果表明,合成反应的最佳工艺条件是：n（St）：n（LMA）：n（AA）=5.7：0.3：4,过氧化苯甲酸叔丁酯用量为5%,反应温度为125℃,得到了多分散指数为1.67,具有良好成膜性的三元丙烯酸共聚物树脂。     

甲基丙烯酸甲酯-丙烯酸共聚物磁性微球的制备及其应用

采用悬浮聚合法制备了甲基丙烯酸甲酯-丙烯酸共聚物(MMA-AA)磁性微球,讨论了单体/水(质量比)、反应温度及反应时间的影响,研究了MMA-AA磁性微球的形态、平均粒径分布及表面官能团状况,将活化后的MMA-AA磁性微球与抗菌药物环丙沙星结合,并用示差脉冲伏安法进行了检测。结果表明,在单体/水为5·0/100、90℃下反应5h可制得具有单分散性的MMA-AA磁性微球;与环丙沙星结合后的MMA-AA磁性微球在-0·365V处有一还原峰,在浓度为6·26×10~(-9)~6·26×10~(-8)mol/L时,其峰电流与环丙沙星浓度具有线性关系,检测下限达到3·20×10~(-9)mol/L。     

Synthesis,characterization, and enzymatic degradation of starch-grafted poly(methyl methacrylate) copolymer films

Graft copolymerization of methyl methacrylate (MMA) onto the corn starch (CS) backbone was carried out in an aqueous medium using ceric ammonium nitrate as an initiator under nitrogen atmosphere. The weight ratio of CS/MMA varied with their composition, as 7/3, 6/4, 5/5, 4/6, and 3/7 were used in this study of the graft efficiency and graft percentage (GP); thus, five different GP CS-g-PMMA copolymers were obtained. The molecular weight of CS-g-PMMA copolymers were measured by using gel permeation chromatography. The structure of CS and CS-g-PMMA copolymer were confirmed by infrared spectra. CS and CS-g-PMMA copolymers were characterized by thermal gravimetric analysis, differential scanning calorimetry, and scanning electron microscopy (SEM). Horowitz-Metzger and Broido methods were applied to investigate the thermal decomposition kinetics of CS-g-PMMA copolymers. The effect of GP on the activation energy of decomposition, crystallization behavior, and morphology was investigated. In addition, the biodegradability of CS-g-PMMA films were also studied by α-amylase treatment with different times. The weight loss of CS-g-PMMA films after α-amylase treatment were calculated. Finally, the morphology of CS-g-PMMA films before and after α-amylase treatment were observed by SEM photograph. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

聚丙烯酸-聚(γ-苄基-L-谷氨酸酯)接枝共聚物的合成与表征

采用溶液聚合法直接合成聚丙烯酸(PAA),通过接枝反应合成了新型两亲性PAA-聚(γ-苄基-L-谷氨酸酯)(PBLG)接枝共聚物,分析了PAA与PBLG的相对分子质量及结构,并通过1H-核磁共振(1H-NMR)、红外光谱(IR)对共聚物进行了表征。结果表明,随着引发剂偶氮二异丁腈用量的增加或聚合温度的升高,PAA的数均相对分子质量减小;随着引发剂正丁胺用量的增加,PBLG的黏均相对分子质量减小。共聚物中含有接枝到PAA链上的疏水性PBLG,同时还含有未反应的亲水性羧基;共聚物在NaCl或NaOH水溶液中形成的球形胶束具有明显的核壳结构。     

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.     

Stress cracking behaviour of poly(methyl methacrylate) and a poly(methyl methacrylate-ethyl acrylate) copolymer

Many organic fluids behave as stress cracking agents on polymers above a critical stress level, while remaining completely inert to the polymer below the critical stress. Because of this property, the proper selection of a stress cracking fluid and testing temperature can provide a non-destructive quality control test. Since many injection moulded parts will perform unacceptably when moulded with residual stresses above a certain level, this type of test is desirable. In this study, the effect of several organic fluids on the stress cracking behaviour of poly(methyl methacrylate) was studied. The experiments were conducted at two temperatures in order to generate a range of critical stress determining conditions. A homopolymer and copolymer of PMMA, having different molecular weight, were investigated and found to have significantly different responses to the stress cracking fluids.     

Effect of water absorption on the izod impact energy of crosslinked poly(methyl methacrylate-acrylic acid) and their composites

Crosslinked poly(methyl methacrylate-acrylic acid) and composites using this crosslinked copolymer as the matrix have been synthesized and evaluated for their potential as bioimplantable materials in design of a new class of bone anchors. The low-velocity impact energy absorption properties of this slightly hydrophilic class of materials were examined by Izod impact testing. In particular, the influence of swelling (by absorption of water) on the impact resistance of the crosslinked copolymer and composites based on this copolymer was investigated. Also, the influence of fiber type and preform architecture on the impact resistance of the composite, in both the dry and swollen states, was investigated. The fracture surfaces and the modes of failure in these tests were examined using scanning electron microscopy. The results indicated that absorption of water leads to about a threefold increase in the impact resistance of the copolymer. However, the increase in the impact resistance of the composite samples after water absorption varied considerably, depending on the type and form of fibrous reinforcement. These results and our understanding of the role of water absorption on the impact resistance of these novel systems are presented.     

Synthesis and characterization of a poly(acrylic acid)‐graft‐methoxy poly(ethylene oxide) comblike copolymer

A methoxy poly(ethylene oxide) (MPEO) grafted poly(acrylic acid) (PAA) comblike copolymer was synthesized by the direct condensation of MPEO onto the PAA backbone in the presence of dicyclohexyl dimethylcarbodiimide (DCC) and 4‐dimethylaminopyridine (DMAP). Its chemical structure was characterized by Fourier transform infrared and ¹H‐NMR spectroscopies. The effects of different catalysts, solvents, reaction temperatures, and reaction times on the grafting degree of the PAA‐g‐MPEO comblike copolymer were investigated. Compared to p‐toluene sulfonic acid, DMAP/DCC as a catalyst markedly increased the grafting degree. The optimum reaction conditions were a tetrahydrofuran/water mixture solvent, a reaction temperature of 50°C, and a reaction time of 168 h. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Pyrolysis-evolved gas-infrared spectroscopic characterization of poly(methyl methacrylate) copolymer glazing materials

The linear temperature programmed pyrolysis of some commercial crosslinked poly(methyl methacrylate) copolymers has been examined by the technique of pyrolysis-evolved gas-infrared analysis. Methyl methacrylate monomer, methanol, and carbon dioxide were detected in the pyrolysis gases. The profiles of rate of evolution against temperature were used to identify the presence of occluded monomer and thermally unstable and groups such as unsaturation. The evolution profiles for methyl methacrylate and methanol were found to be characteristic for each type of crosslink. Evolution of methanol between 250°C and 300°C, and between 300°C and 350°C has been attributed to condensation reactions of carboxylic acid and primary amide groups, respectively, with adjacent ester groups. The evolution profiles were used to distinguish between samples from different manufacturers, and to identify material in aircraft canopies.     

Synthesis and characterization of poly(methyl methacrylate) star polymers

Star-branched poly(methyl methacrylate)s (PMMA) were synthesized by linking ‘living’ arms (produced by anionic polymerzation) with ethylene glycol dimethacrylate. Stars having arm molecular weights of 10000 and 40000 and between 4.9 and 18.7 branches were produced. The polymers were characterized using light scattering, size exclusion chromatography, and viscometry. It was found that well-defined PMMA stars were obtained only at the higher (40000) arm molecular weight. The stars prepared using the lower molecular weight (c. 10000) arms contained very high molecular weight gel components.     

Synthesis and characterization of novel poly(aniline-co-m-aminoacetophenone) copolymer nanocomposites using dodecylbenzene sulfonic acid as a soft template

A series of dodecylbenzene sulphonic acid (DBSA) doped poly(aniline-co-m-aminoacetophenone) copolymer composites of different compositions were synthesized in micellar solution of DBSA to obtain nanosphere morphology with enhanced processability. The plausible mechanism for the formation of poly(aniline-co-m-aminoacetophenone)-DBSA copolymer composite has been presented. These DBSA doped copolymer composites were characterized by UV–Visible, FTIR spectroscopy and XRD analysis techniques. UV–Vis absorption spectrum of the composites showed 325 and 637 nm which corresponds to the π–π* and n–π* transition. In FTIR spectroscopy a broad band around 2,924 cm^?1 corresponds to C–H vibration of DBSA indicating good agreement with the characteristic bands of DBSA. The sharp band at 1,292 cm^?1 is assigned to C–N stretching mode of vibration of N–Ph–N units. The X-ray diffraction of composites reveals that these composites are amorphous in nature. The number of diffraction peaks decreased with increase in the m-aminoacetophenone content. It indicates that these composites are amorphous in nature. Morphological studies (SEM) reveal that these composites have a spherical morphology with the average size of 100–200 nm. These composites exhibit electrical conductivity value of 0.744 × 10^?3 S/cm and enhanced solubility than polyaniline. Moreover, at the presented work, the DBSA doped copolymer composites were obtained in high yields by keeping an oxidant to co-monomer ratio of 1:1.     

Synthesis and thermal properties of poly(methyl methacrylate)‐poly(L‐lactic acid)‐poly(methyl methacrylate) tri‐block copolymer

Poly(methyl methacrylate)‐poly(L ‐lactic acid)‐poly(methyl methacrylate) tri‐block copolymer was prepared using atom transfer radical polymerization (ATRP). The structure and properties of the copolymer were analyzed using infrared spectroscopy, gel permeation chromatography, nuclear magnetic resonance (¹H‐NMR, ¹³C‐NMR), thermogravimetry, and differential scanning calorimetry. The kinetic plot for the ATRP of methyl methacrylate using poly(L ‐lactic acid) (PLLA) as the initiator shows that the reaction time increases linearly with ln[M]₀/[M]. The results indicate that it is possible to achieve grafted chains with well‐defined molecular weights, and block copolymers with narrowed molecular weight distributions. The thermal stability of PLLA is improved by copolymerization. A new wash‐extraction method for removing copper from the ATRP has also exhibits satisfactory results. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Swelling behavior of expandable poly(methyl methacrylate-acrylic acid)/polymethyl methacrylate bio-composites with different crosslinking densities

The volume shrinkage of poly(methyl methacrylate-acrylic acid) (PMMA) bone cement was mainly tackled by the different types and contents of the hydrophilic additives. While the crosslinking density was assumed to regulate the hydrophilic group amounts and 3D network structures in the additives, which influenced the absorption and swelling capacity of the PMMA-based bone cement. In this study, the expandable PMMA/polymethyl methacrylate bio-composites (EBC) with different N, N-methylenebisacrylamide (MBA) contents were synthesized to investigate the relationship between the crosslinking density and swelling performance, and also promoted the absorption and swelling properties before the solidification of EBC. The results demonstrated that the equilibrium absorption ratio and the equilibrium swelling ratio both exhibited a normal distribution with the various MBA content. In addition, the controlled absorption ratio (7.3–60.2%) and swelling ratio (8.5–61.8%) of EBC could be obtained by altering crosslinking density in the system. Furthermore, EBC could obtain a similar equilibrium absorption ratio and equilibrium swelling ratio with different mechanical properties, which provided more options for meeting the requirements of EBC in different clinical settings.     

聚(丙烯酸-丙烯酰胺)接枝辛基酚聚氧乙烯醚丙烯酸酯两亲性共聚物的合成及表征

以辛基酚聚氧乙烯醚丙烯酸酯(C8PhEO10Ac)为大分子单体,丙烯酸(AA)、丙烯酰胺(AM)为共聚单体,采用大分子单体接枝共聚法,制备了一种两亲性接枝共聚物(AA-AM-g-C8PhEO10Ac),用静态光散射(SLS)与GPC联用技术测得接枝共聚物的分子量为9.51×105,用FTIR、1H NMR和TG/DTA等手段对共聚物的结构及性能进行了表征。采用透射电子显微镜(TEM)对聚合物在水溶液中的自组装行为进行了初步研究。结果表明,AA-AM-g-C8PhEO10Ac在水溶液中自组装,形成球型胶束,随着浓度增大,趋向于形成更大的自组装体。     

Synthesis and characterization of poly(p-phenylene sulfide sulfone/ketone) copolymer

Summary High molecular weight poly(phenylene sulfide sulfone/phenylene sulfide ketone) copolymer was synthesized by the step polycondensation of sodium sulfide (Na₂S·xH₂O) with 4,4^′-dichlorobenosulfone (DCDPS), 4,4^′-difldibenzophenone (DFBP) between 180∼202 °C at normal pressure. The copolymer was characterized by FT-IR spectrum, UV spectrum, ¹H-NMR spectrum, X-ray diffraction and small angle light scattering (SALS), DSC and TGA. The more ketone in the copolymer chain, the better thermal properties of the PPSS/Ks resins have. The copolymer was found to be amorphous but has little local ordering structures with the content of ketone in the range of 0∼45% which is different from other high pressure polymerization.     

Study of polymer blends of poly(acetylene) with poly(methyl methacrylate) and methyl methacrylate-butadiene-styrene copolymer

Summary Electroactive polymer blends of polyacetylene (PA) with poly (methyl methacrylate) (PMMA) or methyl methacrylate-butadien-styrene (MBS) copolymer were prepared in situ as free-standing films or powders by polymerization of acetylene in the presence of PMMA or MBS-copolymer, using Luttinger's catalyst. Blends of different composition were studied by infrared spectroscopy and electrical conductivity measurements. Environmental stability of pristine and doped PA was improved to some extent in the presence of PMMA.     

聚(N-异丙基丙烯酰胺)/聚丙烯酸半互穿网络微凝胶的合成及表征

利用IPN技术合成了一种具有温度和pH双重敏感性的聚（N-异丙基丙烯酰胺）/聚丙烯酸半互穿网络微凝胶（PNIPAM/PAAc semi-IPN）。这种微凝胶在酸性条件下发生典型的体积相转变;而在弱碱性条件下,当温度低于聚（N-异丙基丙烯酰胺）（PNIPAM）微凝胶的体积相转变温度（VPTT）时,微凝胶的粒径随着温度的上升而增大,当温度达到VPTT后,粒径突然急剧减小,并随着温度的逐渐上升而减小,最终趋向平衡。     

Synthesis and characterization of poly(hydroxamic acid) chelating resin from poly(methyl acrylate)‐grafted sago starch

A new chelating ion‐exchange resin containing the hydroxamic acid functional group was synthesized from poly(methyl acrylate) (PMA)‐grafted sago starch. The PMA grafted copolymer was obtained by a free‐radical initiating process in which ceric ammonium nitrate was used as an initiator. Conversion of the ester groups of the PMA‐grafted copolymer into hydroxamic acid was carried out by treatment of an ester with hydroxylamine in an alkaline solution. The characterization of the poly(hydroxamic acid) chelating resin was performed by FTIR spectroscopy, TG, and DSC analyses. The hydroxamic acid functional group was identified by infrared spectroscopy. The chelating behavior of the prepared resin toward some metal ions was investigated using a batch technique. The binding capacities of copper, iron, chromium, and nickel were excellent and the copper capacity was maximum (3.46 mmol g⁻¹) at pH 6. The rate of exchange of the copper ion was very fast that is, t_1/2 < 5 min. It was also observed that the metal ion‐sorption capacities of the resin were pH‐dependent and its selectivity toward the metal ions used is in the following order: Cu²⁺ > Fe³⁺ > Cr³⁺ > Ni²⁺ > Co²⁺ > Zn²⁺ > Cd²⁺ > As³⁺ > Pb²⁺. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1256–1264, 2001     

Synthesis and characterization of amphiphilic graft copolymers with hydrophilic poly(acrylic acid) backbone and hydrophobic poly(methyl methacrylate) side chains

A series of well-defined amphiphilic graft copolymers containing hydrophilic poly(acrylic acid) backbones and hydrophobic poly(methyl methacrylate) side chains were synthesized by successive atom transfer radical polymerization followed by the selective hydrolysis of poly(methoxymethyl acrylate) backbone. Grafting-from strategy was employed for the synthesis of graft copolymers with narrow molecular weight distributions. Hydrophobic side chains were connected with the backbone through stable C-C bonds instead of ester connections. The backbone can be easily hydrolyzed to poly(acrylic acid) with HCl without affecting the hydrophobic side chains. The amphiphilic graft copolymers can form stable micelles in water. The critical micelle concentration was determined by fluorescence spectroscopy. The micellar morphologies were found to be vesicles by transmission electron microscopy and changed to spheres with the addition of NaCl.