聚氨酯／聚甲基丙烯酸甲酯互穿聚合物网络的研究

本文对(蓖麻油-聚乙二醇)聚氨酯/聚甲基丙烯酸甲酯(PU/PMMA)互穿聚合物网络(IPN)体系进行了研究.实验结果表明:IPN的力学性能受网络化学构型控制.在PU/PMMA为25/75时,应力-应变曲线出现屈服点,产生类似皮革行为,并在此点抗张强度最高,表现明显的协同效应.动态力学性能及电镜均证明该体系相分离十分严重,通过加入扩链剂及网间交联剂能显著改善两组分相容性,其中网间交联剂效果最好。     

聚环氧丙烷聚氨酯／聚（甲基丙烯酸甲酯—苯惭烯）IPN的研究

改变聚（甲基丙烯酸甲酯－苯乙烯（Ｐ（ＭＭＡ－ｃｏ－Ｓｔ）中 甲基丙烯酸甲酯的含量（ＷＭＭＡ），通过一步法合成出聚环氧氯丙烷聚氨酯（ＰＵ（ＰＥＣＨ）／Ｐ（ＭＭＡ－ｃｏ－Ｓｔ）ＩＰＮ．ＤＳＣ、ＴＥＭ和动态粘弹谱研究结果表明：当Ｐ（ＭＭＡ＿ｃｏ－Ｓｔ）中ＷＭＭＡ大于０．６时，ＩＢＮ仅有一个Ｔｇ；当ＷＭＭＡ小于０．４时，ＩＰＮ有２个Ｔｇ，ＴＥＭ上出现相区，Ｐ（ＭＭＡ－ｃｏ－Ｓｔ）深度参数（δ）及δ的氢键作     

利用FTIR光谱仪研究PU／PMMA IPN初期反应动力学

本文用FTIR光谱仪研完聚醚聚氨酯/聚甲基丙烯酸甲酯(PU/PMMA)互穿聚合物网络(IPN)的初期反应动力学.实验结果表明:该体系IPN在生成过程中动力学不同步是造成相容性较差的原因之一,提高反应温度和增加PMMA的引发剂用量有利于反应同步进行.增加PMMA的含量,使PU反应速度加快是PMMA"溶剂效应”的结果;增加PU含量,使PMMA反应速度减慢是PU的“笼壁效应”结果.聚醚聚氨酯及聚甲基丙烯酸甲酯初期反应均属一级反应动力学.     

聚环氧氯丙烷聚氨酯／聚（甲基丙烯酸甲酯－苯乙烯）IPN的研究

改变聚（甲基丙烯酸甲酯－苯乙烯）（Ｐ（ＭＭＡ－ｃｏ－Ｓｔ）中甲基丙烯酸甲酯的含量（Ｗ_（ＭＭＡ）），通过一步法合成出聚环氧氯丙烷聚氨酯（ＰＵ（ＰＥＣＨ）／Ｐ（ＭＭＡ－ｃｏ－Ｓｔ）ＩＰＮ．ＤＳＣ、ＴＥＭ和动态粘弹谱研究结果表明：当Ｐ（ＭＭＡ－ｃｏ－Ｓｔ）中Ｗ_（ＭＭＡ）大于０．６时，ＩＰＮ仅有一个Ｔｇ；当Ｗ_（ＭＭＡ）小于０．４时，ＩＰＮ有２个Ｔ_ｇ，ＴＥＭ上出现相区，Ｐ（ＭＭＡ－ｃｏ－Ｓｔ）溶度参数（δ）及δ的氢键作用分量（δｈ）与相态、力学性能有密切关系。     

聚环氧氯丙烷聚氨酯／聚甲基丙烯酸甲酯互穿网络聚合物的相容性与力学性能

用同步法合成了聚环氧氯丙烷聚氨酯／聚甲基丙烯酸甲酯互穿网络聚合物［ＰＵ（ＰＥＣＨ）／ＰＭＭＡＩＰＮ］，调节ＩＰＮ中两组分组成比制备出由完全弹性体、增强弹性体、增韧塑料到脆性塑料多种高聚物合金材料．用ＤＳＣ、动态力学谱、ＴＥＭ对ＩＰＮ的研究结果表明，ＰＵ（ＰＥＣＨ）／ＰＭＭＡＩＰＮ的两组分是完全相容的；同时对各种组成比的ＩＰＮ材料进行力学性能测试，用相容性ＩＰＮ中互穿、缠结结构解释其力学行为，并用ＳＥＭ对断面形貌进行了观察解释．     

端羟基聚丁二烯型聚氨酯/聚苯乙烯(或聚甲基丙烯酸甲酯)互穿网络的形态和玻璃化转变

The morphology structure and glass transition behavior of polybutadiene-based polyuretha-ne/polystyrene (or polymethyl methacrylate) interpenetrating polymer network (PU(HTPB)/ PSt-IPN, PU(HTPB)/PMMA-IPN) were investigated by TEM and DSC. TEM showed that the phase inversion of PU(HTPB)/PSt-IPN occurred in the concentration of 25% PU(HTPB), and the size of dispersed phase domains of the IPN formed was smaller in the concentration about 50% PU(HTPB). Increasing DVB content or proportion of NCO to OH enhanced in-terpenetration of two components. All of IPN samples exhibited special cellular structure. According to the fact that PU(HTPB) was formed first,a formation mechanism of the struc-ture was proposed.     

聚氨酯／聚（苯乙烯－甲基丙烯酸甲酯－甲基丙烯酸）互穿聚合物网络的研究

研究了（蓖麻油－聚乙二醇）聚氨酯／聚（苯乙烯－甲基丙烯酸甲酯－甲基丙烯酸）（ＰＵ／Ｐ（Ｓｔ－ＭＭＡ－ＭＡＡ））互穿聚合物网络（ＩＰＮ）．动态力学性能及透射电镜结果均表明该体系相分离较严重；ＩＰＮ具有两个玻璃化转变温度，它们有不同程度的内移，形成一定程度分子水平的混合，而ＩＰＮ（５０／５０）其分子混合水平较大，互穿缠结程度较高。形成ＩＰＮ后，其力学性能得以改善。透射电镜结果表明，聚氨酯网的交联密度直接影响ＩＰＮ的相区尺寸。形成ＩＰＮ后热稳定性提高，易于降解断链的Ｓｔ－ＭＭＡ－ＭＡＡ单体起到了自由基消除剂的作用。     

聚氨酯聚二甲基硅氧烷半IPN透气性研究

近年来,互穿聚合物网络(IPN)的开发受到了广泛的关注。以聚氨酯为一组分,聚丙烯腈、聚酯及环氧树脂等为另一组分的IPN体系的研究已有报道,而聚氨酯与有机硅的IPN体系的研究报道很少。在本文中,我们对聚氨酯(PU)与聚二甲基硅氧烷(PDMS)半IPN的透气性与结构的关系进行了研究。     

交联密度对聚氨酯／聚苯乙烯互穿聚合物网络动态力学性能…

采用同步法合聚氨酯／聚苯乙烯互穿聚合物网络，通过改变ＮＣＯ／ＯＨ比、三元醇／二元醇比、异氰酸酯类型、多元醇分子量、二乙烯苛苯含量及丙烯酸β－羟乙酸的含量，研究了单网及网间交联密度对ＰＵ／ＰＳＩＰＮ动态力学性能影响的规律。结果表明：对相容性差的ＰＵ／ＰＳＩＮＰ体系，要用增加交联密度，加快网络固化速度导致“强迫互容”、能提高两网的互穿与缠结，增进组份的互容，但单网固化速度过快相容性反而下降。     

Polyepichlorohydrin polyurethane/poly(methyl methacrylate) interpenetrating polymer networks

Polyurethane (PU) based on polyepichlorohydrin/poly(methyl methacrylate) (PECH/PMMA) interpenetrating polymer networks (IPNs) was synthesized by a simultaneous method. The effects of composition, hydroxyl group number of PECH, NCO/OH ratio and crosslinking agent content in IPNs were investigated in detail. Some other glycols, such as poly(ethylene glycol), poly(propylene glycol) and hydroxyl-terminated polybutadiene, were also used to obtain PU/PMMA IPNs. The interpenetrating and fracture behaviors of the IPNs are explained briefly.     

聚甲基丙烯酸甲酯/二氧化硅杂化材料制备与性能

溶胶-凝胶;聚硅酸;聚甲基丙烯酸甲酯/二氧化硅杂化材料制备与性能     

Stereocomplex Formation of Atactic Poly(methyl methacrylate)

Stereocomplexes formed in atactic poly(methyl methacrylate) (a-PMMA) films cast form different solvents were studied by means of Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). The growth of stereocomplex was a function of annealing temperature and annealing time, respectively.     

聚甲基丙烯酸甲酯与聚醋酸乙烯酯共混的红外光谱研究

用红外光谱(FTIR)研究了聚甲基丙烯酸甲酯(PMMA)与聚醋酸乙烯酯(PVAc)共混体系相容性,在160℃以上共混体系发生相分离;分相体系与非分相体系的FTIR谱明显不同;共混体系的FTIR谱不能从两统组分红外光谱简单加和得到;结果表明大分子构象发生了变化,PMMA/PVAc体系相容可能是大分子构象熵变所致。     

Synthesis of Polystyrene and Polystyrene/Poly(methyl methacrylate) Nanoparticles

Summary: Polystyrene nanosize particles have been synthesized by a differential microemulsion polymerization process involving the use of a small amount of poly(methyl methacrylate) as the seeds. Sodium dodecyl sulfate and ammonium persulfate were used as the surfactant and initiator, respectively. The effects of various reaction conditions on the particle size have been investigated. Particle sizes of less than 20 nm have been achieved at milder conditions than those previously reported in the literature.

An HRTEM image of PS/PMMA nanoparticles.     

脂肪族聚碳酸酯型聚氨酯/聚甲基丙烯酸甲酯互穿网络聚合物的研究

用同步法合成了聚碳酸亚丙酯聚氨酶／聚甲基丙烯酸甲醇互穿网络聚合物（PPCPU／PMMA，IPN），调节IPN中两组分配比制备出多种高聚物共混物。用DSC、TEM对IPN的研究结果表明．PPCPU／PMMA之IPN的两组分是互不相容的。同时对各种组成比的IPN材料进行力学性能测试，并用SEM对断面进行了观察，发现IPN的密度大于相应体系体积加和值。     

Preparation of Polypyrrole/Poly(methyl methacrylate) Core-Shell Nanoparticles in Four-Component Microemulsion Media

Electrically conductive polypyrrole (PPy)/poly(methyl methacrylate) (PMMA) core-shell nanoparticles were synthesized by two-step microemulsion polymerization. PPy core particles were prepared in a four-component microemulsion system, which was formed with surfactant cetyltrimethyl ammonium bromide (CTAB), cosurfactant n-pentanol, water, and pyrrole. Ferric chloride and iodine was added as the oxidant and the dopant, respectively. Then the PPy nanoparticles were coated with PMMA to prepare PPy/PMMA core-shell nanoparticles. The morphology of PPy/PMMA core-shell nanoparticles was characterized with transmission electron microscopy (TEM). Fourier transform infrared (FTIR) spectroscopy was used to characterize the structure of the samples. The electrical conductivities of samples were studied by a Hall effect testing instrument. Despite being coated with a layer of insulation, the conductivity of the composite PPy/PMMA core-shell nanoparticles could still reached to 7.856 × 10^?1 S/cm.     

Poly(methyl methacrylate) encapsulation of calcium carbonate particles

Dispersed calcium carbonate particles are encapsulated with poly(methyl methacrylate). The optimum condition for the polymerization is investigated; and the encapsulated particles are characterized by spectrophotometric analysis, acid decomposition, thermal analysis, and microscopic observation. From the conversion comparison of the MMA monomer it is found that the optimum concentration of polymerization initiator is 1.58 × 10^?3 mol/L. The highest yield of encapsulation is obtained at 250 rpm with a concentration of 0.5 wt % surfactant (sodium dodecyl benzene sulfonate). A comparison of the Fourier transform IR spectra distinctly indicates the formation of PMMA on the surface of the calcium carbonate particles. The outcome of an acid decomposition test proves that the PMMA coating protects the particles. In addition, thermal analyses and microscopic observation characterize the PMMA on the surface of encapsulated particles. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4063–4073, 2004     

Electrorheology of Multiwalled Carbon Nanotube/Poly(methyl methacrylate) Nanocomposites

Summary: Multiwalled carbon nanotube (MWNT) nanocomposites dispersed in a poly(methyl methacrylate) (PMMA) matrix were prepared via suspension polymerization, in which radicals induced on the outer wall of the MWNTs by 2,2′‐azoisobutyronitrile initiate the grafting of PMMA. The synthesized MWNT/PMMA nanocomposite particles were found to have a spherical shape and exhibit a high electrical conductivity, mainly as a result of the carbon nanotubes. A suspension was prepared with MWNT/PMMA particles in insulating silicone oil and its electrorheological properties were investigated by controlling applied direct current (DC) electric field strengths.

Flow curve possessing a region analogous to the coexistence curve.     

Compatibilization of blends of polybutadiene and poly(methyl methacrylate) with poly(butadiene-block-methyl methacrylate)

Compatibilization of blends of polybutadiene and poly(methyl methacrylate) with butadiene-methyl methacrylate diblock copolymers has been investigated by transmission electron microscopy. When the diblock copolymers are added to the blends, the size of PB particles decreases and their size distribution gets narrower. In PB/PMMA7.6K blends with P(B-b-MMA)25.2K as a compatibilizer, most of micelles exist in the PMMA phase. However, using P(B-b-MMA)38K as a compatibilizer, the micellar aggregation exists in PB particles besides that existing in the PMMA phase. The core of a micelle in the PMMA phase is about 10 nm. In this article the influences of temperature and homo-PMMA molecular weight on compatibilization were also examined. At a high temperature PB particles in blends tend to agglomerate into bigger particles. When the molecular weight of PMMA is close to that of the corresponding block of the copolymer, the best compatibilization result would be achieved. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36 : 85–93, 1998