Tape Casting Slip Preparation by in Situ Polymerization

The present work describes the polymerization of methylmethacrylate monomer into polymethylmethacrylate (PMMA), in the presence of either coarse or ultrafine alumina powder. The flexibility of the material was modified by addition of either butylbenzyl phthalate (S-160), or butylacrylate (BA) monomer as plasticizers. It was found that BA is more compatible than S-160 in the PMMA system. A density of 97%–99% was reached with ultrafine alumina. The maximum tensile strength of the green and sintered tapes was 10 and 140 MPa, respectively. Due to improved homogeneity in the polymerized slip, the sintered tapes prepared by in situ polymerization were stronger and denser than those prepared by conventional blending of commercial PMMA.     

MCPA6/气相SiO_2复合材料的制备及性能研究

以氢氧化钠为催化剂,N-乙酰己内酰胺为活化剂,通过阴离子原位聚合法制备浇铸尼龙6(MCPA6)/气相Si O2复合材料,并利用扫描电子显微镜、差示扫描量热、热重分析、力学性能测试等方法研究了气相Si O2用量对复合材料的微观形态、结晶性能、吸水率、热稳定性能及拉伸和冲击性能的影响。结果表明,经硅烷偶联剂(KH550)处理的气相Si O2能均匀分布在MCPA6中;气相Si O2可促进MCPA6的结晶,降低吸水率,当气相Si O2用量为己内酰胺质量的0.5%时,复合材料的吸水率最低,比MCPA6降低16%;复合材料的热稳定性提高,当气相Si O2用量为己内酰胺质量的2.5%时,复合材料起始分解温度和失重速率最大时分解温度分别比MCPA6提高98.8℃和38℃;随着气相Si O2用量增加,复合材料的拉伸和冲击性能均呈先升高后降低的趋势,当气相Si O2用量为己内酰胺质量的0.5%时,拉伸强度、断裂伸长率及缺口冲击强度较MCPA6分别提高10%,6%和81%。     

原位聚合制备聚甲基丙烯酸甲酯/石墨烯复合材料

采用原位聚合的方法,将石墨烯和甲基丙烯酸(MMA)通过超声共混后引发聚合,制备了聚甲基丙烯酸甲酯(PMMA)/石墨烯复合材料。采用原子力显微镜、透射电子显微镜、扫描电子显微镜、傅立叶变换红外光谱仪和X射线衍射仪对PMMA/石墨烯的结构和形貌进行了表征,复合材料的拉伸性能和导电率分别采用拉力试验机和四探针金属/半导体电阻率测量仪器测试。结果表明,石墨烯均匀地分散在PMMA中,加入石墨烯后,PMMA的拉伸应变弹性模量、最大拉伸应变得到了大大提高。而且,当石墨烯含量由0增加到1%时,复合材料的电导率由1×10-14 S/cm提高到了8.89×10-2 S/cm,PMMA由原来的绝缘材料改性为导电材料。     

原位乳液聚合法制备聚苯乙烯-丙烯酸酯/纳米蒙脱土复合乳液

通过原位乳液聚合法,采用5种不同类型的蒙脱土制备了聚苯乙烯-丙烯酸酯/蒙脱土复合乳液。讨论了各种影响因素对复合乳液制备及乳液涂膜性能的影响,采用正交实验的方法对实验工艺进行优化,并采用X射线衍射(XRD)对复合物结构进行了分析。结果表明:蒙脱土在复合物中呈现纳米级分散,形成了插层型结构。钠型蒙脱土制备出的复合乳液性能较好,蒙脱土含量增加对单体聚合有一定阻聚作用。     

原位乳液聚合法制备聚苯乙烯一丙烯酸酯／纳米蒙脱土复合乳液

通过原位乳液聚合法，采用5种不同类型的蒙脱土制备了聚苯乙烯一丙烯酸酯／蒙脱土复合乳液。讨论了各种影响因素对复合乳液制备及乳液涂膜性能的影响，采用正交实验的方法对实验工艺进行优化，并采用X射线衍射（XRD）对复合物结构进行了分析。结果表明：蒙脱土在复合物中呈现纳米级分散，形成了插层型结构。钠型蒙脱土制备出的复合乳液性能较好，蒙脱土含量增加对单体聚合有一定阻聚作用。     

A Dip-Coating Process for the Preparation of PZT Microtubes

PZT microtubes have been fabricated by dip coating of aqueous PZT powder slurry on vermicelli, followed by burnout of the vermicelli and sintering. The water-absorbing character of the vermicelli made a thin layer of PZT slurry to gel on its surface during dip coating. Thickness of the gel on the surface of the vermicelli depends on the dipping time. The green PZT layer thickness in the range of 140–190 μm could be achieved for a dipping time of 30–120 s. Microtubes having an inner diameter of nearly 500 μm with wall thickness in the range of 120–160 μm could be prepared by this process.     

Preparation and Characterization of Novel Polyimide/SiO2 Nano-hybrid Films by In Situ Polymerization

A silicon-based aromatic polyimide (PI) containing pendent aryl rings was synthesized by solution polycondensation of a silicon-containing diamine with 4,4′-(hexafluoroisopropylidene)diphthalic anhydride. Its nano-hybrids with different colloidal SiO₂ concentrations were synthesized by in situ polymerization. The reactions were carried out in presence of 3-aminopropyltriethoxysilane as a coupling agent. The inclusion of the coupling agent in the polymer chain and its co-condensation with SiO₂ nanoparticles afforded a silica network that was interconnected chemically with the PI matrix. The chemical structure of the hybrid materials was analyzed by Fourier transform infrared spectroscopy and energy dispersive X-ray spectroscopy. The morphology of the hybrid films and the surface roughness were characterized by scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. The results indicated that nanometer-scale inorganic particles were homogeneously dispersed throughout the PI matrix with 50–70 nm size range. The best results and favorable miscibility between polymer and silica phases in the nano-hybrids were obtained when up to 40 wt% nanoparticles were introduced into the backbone of PI matrix.     

原位聚合聚氯乙烯树脂的合成及性能

研究了氯乙烯悬浮聚合时添加氯化聚乙烯(CPE)冲击改性剂、CaCO3填料、润滑剂及热稳定剂对聚合反应的影响，并对得到的可直接加工的原位聚合聚氯乙烯(RTUPVC)树脂的性能进行了表征。结果发现：CPE和CaCO3的加入均使达到相同压降的聚合时间缩短，氯乙烯聚合转化率相应减小；RTUPVC树脂的粒径随CPE粒径和用量的增大而增大，而CaCO3含量对RTUPVC树脂粒径影响不大；润滑剂和热稳定剂的加入，对聚合反应起延缓作用，但对RTUPVC树脂粒径影响不大；RTUPVC树脂加工塑化时间随CPE含量的增加而减少；相同CPE用量时，RTUPVC树脂的冲击强度和拉伸强度明显高于PVC/CPE共混物。     

Pinewood Composite Prepared by In Situ Graft Polymerization of Epoxy Monomer

Composites were prepared by graft polymerization of glycidyl methacrylate (GMA) into low‐quality Brazilian pinewood. Oven‐dried pinewood samples were impregnated with GMA (1.5 wt% of benzoyl peroxide as catalyst), polymerized by heat at 90°C for 10 h, and washed with acetone to leach the unreacted chemicals. The characterization was performed by treatability parameters, scanning electron microscopy images, ATR‐IR spectroscopy, TGA, differential scanning calorimetry (DSC), mechanical properties, water uptake and dimensional stability measurements, and decay resistance tests. The main results showed that the conversion of monomers into grafted polymers was high—up to 85%. The graft polymerization was confirmed by reduction (∼15°C lower) in the temperature of the main thermal event via DrTG and DSC. A decrease in OH band and an increase of peaks corresponding to CO and C O bonds in ATR‐IR also confirmed the grafting. The hygroscopicity and wetting were reduced ∼10 times, dimensional stability improved about 70%, and mechanical properties improved between 55 and 85% after the graft polymerization. Decay resistance also increased both against brown and white rot fungi. The graft polymerization of glycidyl methacrylate can improve many technological properties of low‐quality pinewood . POLYM. COMPOS., 38:597–603, 2017. © 2015 Society of Plastics Engineers     

有机蒙脱土对原位插层聚合PMMA性能的影响

利用原位插层聚合法在玻璃模具中合成了聚甲基丙烯酸甲酯/有机蒙脱土(PMMA/OMMT)纳米复合材料,实现了层状OMMT在PMMA基体中剥离成纳米片状OMMT。用DSC和DMA对一维纳米OMMT片层环境下PMMA链的松弛性进行了表征。DMA测试结果显示,复合材料的玻璃化转变温度比纯PMMA高,且对应峰的强度随着OMMT用量的增加而降低,表明纳米片状OMMT对其周围的PMMA链的运动具有限制作用。     

骨瓷注浆泥料的配制

从生产实际出发并结合作者的实践经验，提出了在骨瓷注浆泥料配制中应注意的问题。     

Preparation of Cinnamon Oil‐Loaded Antibacterial Composite Microcapsules by In Situ Polymerization of Pickering Emulsion Templates

In this study, the cinnamon oil (CMO)‐loaded antibacterial composite microcapsules with silicon dioxide (SiO₂)/poly(melamine formaldehyde) (PMF) hybrid shells are effectively and facilely constructed by in situ polymerization of SiO₂ nanoparticle–stabilized Pickering emulsion templates. The morphological structure, composition, and thermal performance of the microcapsules are determined by scanning electronic microscopy, Fourier transform infrared spectroscopy, and thermal gravimetric analysis. In addition, in vitro CMO release and antimicrobial investigations of the microcapsules are also performed, respectively. The results demonstrate that the microcapsules own an approximately spherical shape with a core–shell structure. Moreover, the micro‐encapsulation of CMO clearly increases its thermal stability, and meanwhile results in obtaining microcapsules with the controlled CMO release and visibly long‐term antimicrobial effects. All the results show that in situ polymerization based on templating Pickering emulsions is an attractive method to construct antibacterial essential oil–loaded microcapsules, which can be served as promising antibacterial materials.     

原位聚合PE/MMT纳米复合材料的流变行为研究

采用蒙脱土(MMT)负载的Ziegler-Natta催化剂,通过原位聚合法制备了不同MMT含量的聚乙烯(PE)/MMT纳米复合材料。利用热重分析(TGA)确定了PE/MMT纳米复合材料中MMT的含量,并使用Haake流变仪分析了MMT含量对PE/MMT纳米复合材料流变行为的影响。结果表明:PE/MMT纳米复合材料的熔体流变行为与高密度聚乙烯(HDPE)和低密度聚乙烯(LDPE)基本一致;复合材料的黏度随MMT含量的增加先升高后降低,其中当MMT含量为4.58%时,其黏度明显低于HDPE和LDPE,该性质有利于复合材料的成型加工;PE/MMT纳米复合材料属于假塑性流体,其非牛顿指数(n)随着温度的升高而增大,随着MMT含量的增加先降后升。     

正硅酸乙酯原位聚合改性淀粉膜的制备和性能

采用正硅酸乙酯(TEOS)原位聚合改性制备了淀粉膜,研究了其性能。当TEOS用量为淀粉的25%时,膜的力学性能最好,拉伸强度和断裂伸长率分别为16.91 MPa和24.88%。此外,还进行了电子能谱仪、扫描电子显微镜、X射线衍射和降解性测试。结果表明,淀粉膜中Si元素含量与添加量吻合,硅羟基与淀粉分子中的羟基发生了脱水缩合反应;淀粉膜表面均一平整,结晶度低,热塑性、降解性良好,是一种可完全生物降解的环保材料。     

SiC部件泥浆浇注工艺

本文论述了影响SiC泥浆性能的几个主要因素,运用SiC粉料Zeta电位随PH值变化曲线作指导,通过PH值调整和改变分散介质,着重研究了SiC泥浆稳定性、泥浆浇注样品的性能和显微结构,获得了浇注性能好、长时间稳定不沉淀的泥浆。分析了浇注过程中的各种影响因素,讨论了泥浆性状对浇注性能及样品烧结后力学性能的影响,最终浇注出大尺寸SiC陶瓷部件。     

乳化剂对一步原位聚合法制备自修复微胶囊的影响

采用一步原位聚合法制备了以脲醛树脂为囊壁,桐油为囊芯的自修复微胶囊。研究了乳化剂种类和用量对微胶囊的影响。采用光学显微镜(OM)、激光粒度分析仪分析了微胶囊的表面形貌、粒径分布及平均粒径。结果表明,OP-10对微胶囊的形成有积极作用,最佳OP-10用量为10%,在此浓度下制备的微胶囊表面光滑,结构致密,粒径分布更均匀,平均粒径较小。     

原位聚合法制备聚对苯二甲酸丙二醇酯／蒙脱土复合材料及其表征

采用原位聚合法制备了聚对苯二甲酸丙二醇酯(PTT)像脱土(MMT)复合材料。X射线衍射和透射电子显微镜扫描结果表明所得复合材料为剥离型或部分剥离型结构。与纯PTT、相比，由于MMT、在PTT基体中达到纳米尺寸分散，PTT／MMT复合材料的热稳定性能、结晶性能和拉伸性能都得到了明显提高。     

MC尼龙/纳米MgO复合材料的制备与性能

采用硫酸铵和碳酸氢铵以及轻烧Mg O粉为原料,利用液相沉淀法制备高纯纳米级Mg O。同时对纳米Mg O进行表面改性,使其可以更好地分散在MC尼龙基体中。将改性后的纳米Mg O,以氢氧化钠为催化剂,甲苯二异氰酸酯为活化剂对MC尼龙进行单体浇铸,制得MC尼龙/Mg O复合材料。结果表明,经纳米Mg O粒子改性后的MC尼龙,其冲击强度和拉伸强度比纯MC尼龙都有所提高,具有增韧和增强的双重效果。     

Water-Based PMMA-Nano-CaCO3 Nanocomposites by In Situ Polymerization Technique: Synthesis,Characterization and Mechanical Properties

Water-based nanocomposite was synthesized using in-situ polymerization of Methyl Methacrylate. Nano-CaCO₃ was added during polymerization along with aqueous solution of surfactant. Quantity of nano-CaCO₃ was varied as 0, 2 and 4% of monomer quantity. XRD gram shows the presence of nano-CaCO₃, which causes the crystalline nature to nanocomposites. TEM images of nano-CaCO₃ show cubic structure. Synthesis of nanocomposite follows pseudo–first-order kinetics polymerization. PMMA-4% CaCO₃ nanocomposite showed significant improvement in UV absorbance and in mechanical properties like adhesion, scratch resistance as compared to neat PMMA and 2% CaCO₃ nanocomposite.     

Molecular Self-Assembled Microcapsules Prepared by In Situ Polymerization Technology for Self-Healing Cement Materials

Monodisperse core–shell microcapsules have been widely used as self-healing cement materials and paid more attentions. A new series of self-assembled microcapsules containing poly(styrene-divinylbenzene) as shell material were prepared by in situ polymerization technology. The microencapsulating process of core material using mixture of epoxy resins and benzyl alcohol was monitored using optical microscopy (OM). Morphology and shell wall thickness of microcapsule were observed using scanning electron microscopy and OM, respectively. The effects of different weight ratios of core–shell and the agitation rates on the physical properties of microcapsules were investigated. The size and surface morphology of microcapsule can be controlled by selecting different processing parameters.