悬浮聚合聚甲基丙烯酸甲酯／蒙脱土纳米复合材料的制备及表征

采用悬浮聚合法制备了聚甲基丙烯酸甲酯／蒙脱土（PMMA/MMT）纳米复合材料，利用X射线衍射仪、透射电子显微镜和傅里叶变换红外光谱等手段表征了复合材料的结构，研究了不同改性剂对复合材料结构的影响。通过热重分析考察了复合材料的热性能。结果表明，通过悬浮聚合可以成功制备剥离型纳米复合材料，PMMA基体与MMT可以产生较强的相互作用。MMT的加入可以显著提高复合材料的热稳定性。当MMT含量为10％（质量分数，下同）时，PMMA的最大分解温度提高了15℃。     

聚甲基丙烯酸甲酯/SiO2纳米复合物的制备

基于纳米SiO2表面羟基与γ-甲基丙烯酰氧基丙基三甲氧基硅烷间的缩合反应,于SiO2表面引入双键.以甲基丙烯酸甲酯为单体,偶氮二异丁腈为引发剂,采用原位自由基聚合的方法,制备了聚甲基丙烯酸甲酯/SiO2纳米复合材料.FTIR和TGA证实聚甲基丙烯酸甲酯大分子链成功接枝在SiO2表面.聚合体系黏度是影响SiO2表面聚甲基丙烯酸甲酯接枝率的关键因素.甲基丙烯酸甲酯浓度为6 mol/L,偶氮二异丁腈浓度为0.05～0.1 mmol/L时,SiO2表面聚甲基丙烯酸甲酯接枝率可达到94％;SiO2用量对表面接枝聚合没有影响.     

碳酸钙/聚甲基丙烯酸甲酯纳米复合粒子制备及表征

研究了纳米碳酸钙存在下的甲基丙烯酸甲酯的无皂乳液聚合。对所得的产品用热甲苯进行抽提,并用TEM、IR、XPS等手段进行分析。结果表明,聚合后纳米碳酸钙粒子表面被PMMA所包覆,并且PMMA不能完全被热甲苯抽提出来,这是由于这部分PMMA是通过化学键接枝在纳米碳酸钙的表面的缘故。     

以SiO2纳米粒子为种子的甲基丙烯酸甲酯乳液聚合

本文采用SiO2纳米粒子作为种子进行了甲基丙烯酸甲酯的乳液聚合。初步探讨了此类种子乳液聚合的过程；也分析了SiO2的用量对所生成的残渣率的影响，SiO2在残渣中的实际含量均比在乳液聚合物中略高，这是由于总有一些单体转移到不含SiO2的自由胶束中进行聚合而造成的。所得的复合乳液聚合物的力学和热学性能测试结果表明材料的这两种性能均随SiO2含量的增加而降低。     

两步反相微乳液法原位制备纳米SiO2/聚甲基丙烯酸甲酯复合微粒

采用两步反相微乳液法原位聚合制备纳米SiO2／聚甲基丙烯酸甲酯(polymethylmethacrylate,PMMA)复合微粒。首先,通过混合2个分别增溶有2种反应物的微乳液,制备纳米SiO2粒子;然后,向混合后的微乳液中滴加单体及引发剂,通过单体的原位聚合反应得到SiO2,PMMA复合微粒。通过相图研究：确定了微乳液法制备复合微粒时初始组分的用量。通过透射电子显微镜、红外光谱、热重分析、X射线光电子能谱等手段对复合微粒进行了表征。结果表明：聚合后的PMMA包覆在SiO2表面．复合微粒的平均粒径为30nm．分散性良好。复合微粒中不能被抽提出来的聚合物占10．08％,这部分聚合物以Si-O-C键形式接枝在SiO2表面。     

纳米SiO2表面聚合物接枝改性的研究

在纳米ＳｉＯ２颗粒表面通过引入过氧基因引发甲基丙烯酸甲酯（ＭＭＡ）聚合，研究了温度、反应时间等对纳米颗粒改性的影响。ＩＲ结果表明，在纳米ＳｉＯ２表面已成功地接枝上聚甲基丙烯酸甲酯（ＰＭＭＡ）。     

PbSe/聚甲基丙烯酸甲酯纳米复合材料的制备及表征

采用超声电化学法制备出水相硒化铅(PbSe)纳米晶体,并将其掺杂到聚甲基丙烯酸甲酯(polymethyl methacrylate,PMMA)材料中,通过本体聚合法制备出PbSe/PMMA纳米复合材科.用X射线衍射、透射电镜、扫描电镜对PbSe纳米晶体和PbSe/PMMA纳米复合材料的形貌进行了表征.结果表明:超声电化...     

原位分散聚合制备聚甲基丙烯酸甲酯/超细碳酸钙复合粒子

为了提高聚合物在超细碳酸钙粒子表面的接枝和包覆,对超细碳酸钙锚固偶氮引发剂及甲基丙烯酸甲酯(MMA)/改性碳酸钙原位分散聚合进行了研究. 碳酸钙粒子经氨基硅烷偶联剂处理后能与偶氮二氰基戊酸反应而实现锚固化,由红外光谱和元素分析证明了偶联和锚固反应.通过锚固在碳酸钙上的偶氮引发剂的引发作用,由MMA分散聚合制备了聚甲基丙烯酸甲酯(PMMA)接枝率高的PMMA/超细碳酸钙复合粒子,PMMA接枝率随聚合转化率增加而增加,而接枝效率随之降低;接枝PMMA的碳酸钙粒子在四氢呋喃和MMA中的分散稳定性明显优于未改性碳酸钙.     

纳米铁粒子表面接枝聚合甲基丙烯酸甲酯

采用直流电弧等离子体法制备纳米铁粉,利用甲基丙烯酸(MAA)和盐酸处理纳米铁粉,通过乳液聚合方法,在纳米铁粉存在下MMA原位聚合,形成纳米铁/聚甲基丙烯酸甲酯复合粒子。分析结果表明,MMA在纳米铁粒子表面接枝聚合,纳米铁粉表面的双键参与了聚合反应,所形成的复合粒子具有核壳结构,这种复合粒子具有较高的稳定性。     

改性纳米SiO2粒子增韧PMMA

采用表面接枝的方法,在室温下用硅烷偶联剂改性纳米（nano）-SiO2,经引发剂引发甲基丙烯酸甲酯聚合包覆,并以其为填充物与聚甲基丙烯酸甲酯（PMMA）熔融共混,制得PMMMnano-SiO2复合材料。力学性能测试表明,随着改性nano-SiO2用量的增加,PMMA／nano-SiO2复合材料的缺口冲击强度和拉伸强度均明显提高,当w（nano—SiO2）为3％时,PMMA／nano—SiO2复合材料的综合力学性能最佳,缺口冲击强度和拉伸强度分别提高了94．7％和28．O％：     

Characterization and Properties of Poly(methyl methacrylate)/Graphene,Poly(methyl methacrylate)/Graphene Oxide and Poly(methyl methacrylate)/p-Phenylenediamine-Graphene Oxide Nanocomposites

In this study, poly(methyl methacrylate)/p-phenylenediamine-graphene oxide, poly(methyl methacrylate)/graphene, and poly(methyl methacrylate)/graphene oxide nanocomposite series were prepared using simple solution blending technique. In poly(methyl methacrylate)/p-phenylenediamine-graphene oxide series, graphene oxide modified with p-phenylenediamine was used to improve its dispersion and interfacial strength with matrix. Morphology study of poly(methyl methacrylate)/p-phenylenediamine-graphene oxide nanocomposite revealed better dispersion of p-phenylenediamine-graphene oxide flakes and gyroid patterning of poly(methyl methacrylate) over the filler surface. Due to nonconducting nature of graphene oxide, there was no significant variation in the thermal or electrical conductivity of these nanocomposites. Thermal conductivity of poly(methyl methacrylate)/p-phenylenediamine-graphene oxide 1.5 was 1.16 W/mK, while the electrical conductivity was found to be 2.3 × 10^?3 S/cm.     

悬浮聚合法制取不同分子量级别的聚甲基丙烯酸甲酯

采用粉状MgCO3 作为分散剂 ,悬浮聚合制取了分子量从 2 4× 10 4 ～ 2 5 4× 10 4 的聚甲基丙烯酸甲酯。考察了温度、引发剂种类和浓度、分子量调节剂、转化率对聚合物分子量的影响规律 ,用粘度法测量了聚合物聚甲基丙烯酸甲酯 (PMMA)的分子量。结果表明 :温度的升高、引发剂浓度的增大、分子量调节剂的加入都会导致分子量的减小 ,随着转化率的提高 ,聚合物的分子量增大。在同等条件下 ,引发剂过氧化苯甲酰 (BPO)聚合所得的分子量较偶氮二异丁腈 (AIBN)高。通过实验 ,得到了满足作者需求的分子量 (96× 10 4 ～ 10 0× 10 4 )的聚合物的聚合条件为 :分散剂MgCO3 用量 1% ,单体∶水相 =1∶2 5 (质量比 ) ,引发剂BPO浓度 0 5 % ,反应温度 70℃ ,反应时间 3h。     

Phase behavior and properties of poly(methyl methacrylate)/poly(vinyl acetate) blends prepared via in situ polymerization

Polymer blends composed of poly(methyl methacrylate) (PMMA) and poly(vinyl acetate) (PVAc) were prepared via radical-initiated polymerization of methyl methacrylate (MMA) in the presence of PVAc. Differential scanning calorimetry and dynamic mechanical analysis were employed to investigate the miscibility and phase behavior of the blends. The PMMA/PVAc blends of in situ polymerization were found to be phase separated and exhibited a two-phase structure, although some chain transferring reaction between the components occurred. The phase separation resulted from the solvent effect of MMA during the in situ polymerization, which was confirmed by the investigation of phase behavior based on solution cast blending. Solubility analysis of the polymerized blends indicated that some chain transferring reaction between the components occurred during the polymerization. An abrupt increase in gel content from 21.2 to 72.4 wt % was observed when the inclusion of PVAc increased from 30 to 40 wt %, and the gel component consisted of the component polymers as shown by infrared spectroscopy studies. The thermogravimetric analysis study indicated that the inclusion of a small amount of PVAc gives rise to a marked stabilization effect on the thermal stability. The PMMA/PVAc blends exhibited increased notched impact properties with the inclusion of 5 wt % PVAc. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 675–684, 1998     

Synthesis and characterization of poly(methyl methacrylate)/montmorillonite nanocomposites by in situ bulk polymerization

Poly(methyl methacrylate)/montmorillonite (MMT) nanocomposites were prepared by in situ bulk polymerization. The results showed that the silicone coupling agent affected the structure and properties of hybrid materials. XRD analysis showed that the dispersion of clay in nanocomposites with silicone‐modified organophilic MMT was more ordered than that in nanocomposites with unmodified organophilic MMT. The glass transition temperature (T_g) of the nanocomposites was 6–15°C higher and the thermal decomposition temperature (T_d) was 100–120°C higher than those of pure PMMA. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2256–2260, 2003     

Preparation of poly(methyl methacrylate)/titanium oxide composite particles via in‐situ emulsion polymerization

Poly(methyl methacrylate) (PMMA)/Titanium oxide (TiO₂) composite particles were prepared via in‐situ emulsion polymerization of MMA in the presence of TiO₂ particles. Before polymerization, the TiO₂ particles was modified by the silane coupling agent, which is crucial to ensure that PMMA reacts with TiO₂ via covalent bond bindings. The structure of the obtained PMMA/TiO₂ composite particles was characterized using Fourier transform infrared spectra (FTIR) and thermogravimetric analysis (TGA). The results indicate that there are covalent bond bindings between PMMA macromolecules and TiO₂ particles. Based on these facts, several factors affecting the resulting PMMA/TiO₂ composite system, such as the type of coupling agents, the mass ratio of the MMA to the modified TiO₂, the emulsifier concentration, and the initiator concentration, etc., were examined by the measurement of conversion of monomers, the gel content of polymers, the percentage of grafting, and the grafting efficiency, using gravity method or TGA method. As a result, the optimized recipe was achieved, and the percentage of grafting and the grafting efficiency could reach 216.86 and 96.64%, respectively. In addition, the obtained PMMA/TiO₂ composite particles were found to a stable colloidal dispersion in good solvent for PMMA. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4056–4063, 2006     

Effect of in situ polymerization conditions of methyl methacrylate on the structural and morphological properties of poly(methyl methacrylate)/poly(acrylonitrile‐g‐(ethylene‐co‐propylene‐co‐diene)‐g‐styrene) PMMA/AES Blends

In this study, the structural and morphological properties of poly(methyl methacrylate)/poly(acrylonitrile‐g‐(ethylene‐co‐propylene‐co‐diene‐g‐styrene) (PMMA‐AES) blends were investigated with emphasis on the influence of the in situ polymerization conditions of methyl methacrylate. PMMA‐AES blends were obtained by in situ polymerization, varying the solvent (chloroform or toluene) and polymerization conditions: method A—no stirring and air atmosphere; method B—stirring and N₂ atmosphere. The blends were characterized by infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and dynamic mechanical analysis (DMA). The results showed that the PMMA‐AES blends are immiscible and present complex morphologies. This morphology shows an elastomeric dispersed phase in a glassy matrix, with inclusion of the matrix in the elastomer domains, suggesting core shell or salami morphology. The occlusion of the glassy phase within the elastomeric domains can be due to the formation of graft copolymer and/or phase inversion during polymerization. However, this morphology is affected by the polymerization conditions (stirring and air or N₂ atmosphere) and by the solvent used. The selective extraction of the blends' components and infrared spectroscopy showed that crosslinked and/or grafting reactions occur on the elastomer chains during MMA polymerization. The glass transition of the elastomer phase is influenced by morphology, crosslinking, and grafting degree and, therefore, T_g depends on the polymerization conditions. On the other hand, the behavior of T_g of the glassy phase with blend composition suggests miscibility or partial miscibility for the SAN phase of AES and PMMA. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis and Surface Properties of Poly(methyl methacrylate)/Poly(ethylene glycol) Binary Brushes

A new kind of binary polymer brushes was synthesized from two immiscible polymers, PMMA and PEG, on GPS‐modified silicon wafers. Surface composition, layer thickness, coverage, chain density, wetting ability, morphology and protein adsorption of the binary brushes were investigated by XPS, ellipsometry, AFM and contact angle measurements. The results show that both PMMA and PEG were successfully grafted onto the surface. The surface coverage and the chain density of PMMA and PEG brushes can be controlled by modulating the reaction temperature and time. This kind of binary polymer brushes exhibits a distinct microphase‐separated structure and excellent protein‐preventing property.

     

Preparation and characterization of poly(methyl methacrylate) beads

The phase behavior of Poly(ethylene terephthalate)/Poly(ethylene‐2,6‐naphthalate)/Poly(ethylene terephthalate‐co‐ethylene‐2,6‐naphthalate) (PET/PEN/P(ET‐co‐EN)) ternary blends in molten state was evaluated from differential scanning calorimetry (DSC) and NMR results as well as optical microscopic observations. Copolymer of ethylene terephthalate and ethylene‐2,6‐naphthalate was prepared by a condensation polymerization, which was a random copolymer with an intrinsic viscosity (IV) of 0.3 dL/g. The phase diagram of the ternary blends revealed that the miscibility of ternary blends in molten state was dependent on the fraction of P(ET‐co‐EN) in the blends and holding time of the blends at high temperatures above 280°C. With increase in the holding time, the fraction of copolymer in the blends necessary to induce the immiscible to miscible transition decreased. For the blends with longer holding time at 280°C, the phase diagram in molten state was irreversible against the temperature, although a reversibility was found for the blends with short holding time of 1 min at 280°C. The irreversibility of phase behavior was not explained simply by the increase of copolymer content produced during heat treatment. Complex irreversible physical and chemical interactions between components and change of phase structure of the blend in the molten state might influence on the irreversibility. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Poly(methyl acrylate-co-methyl methacrylate)/montmorillonite nanocomposites fabricated by soap-free emulsion polymerization

The exfoliated poly(methyl acrylate-co-methyl methacrylate)/montmorillonite (MMT) nanocomposite latex solutions fabricated by soap-free emulsion polymerization were able to cast into a film. The films were transparent and ductile unless more than 5 wt% of MMT was incorporated. With the MMT content higher than 5 wt%, the inflammable residuals of nanocomposites after combustion could preserve their original film profile acting like an inflammable scaffold. Moreover, as 20 wt% MMT was incorporated, the yield strength of the films was increased up to 20 times and Young’s modulus up to 2,000 times. However, the water vapor permeability coefficient of the films was only decreased down to its half value. This unexpected behavior of permeability was associated with the decrease of T _g as the content of MMT was increased, owing to the large difference of the reactivity ratios between methyl acrylate and methyl methacrylate monomers and their differential absorption to the MMT during copolymerization.     

Synthesis and properties of poly(methyl methacrylate)/montmorillonite (PMMA/MMT) nanocomposites

PMMA/MMT nanocomposites were successfully synthesized via in situ intercalative polymerization, and characterized by means of wide‐angle X‐ray diffractometry, transmission electron microscopy, thermal gravimetric analysis, dynamic mechanical analysis and Fourier‐transform infrared analysis. The nanocomposites possess partially exfoliated and partially intercalated structure, in which the silicate layers are exfoliated into nanometre secondary particles with thickness of less than 20 nm and uniformly dispersed in the polymer matrix. In comparison with pure PMMA, the thermal stability, glass transition temperature, and mechanical properties of the polymer are notably improved by the presence of the nanometric silicate layers. It was found that part of the PMMA chains in the nanocomposites are well immobilized inside and/or onto the layered silicates and, therefore, the unique properties of the nanocomposites result from the strong interactions between the nanometric silicate layers and the polymer chains. Copyright © 2003 Society of Chemical Industry