多组分乳胶IPN′s体系的相容性和阻尼性能

用动态粘弹谱仪研究多组分乳胶ＩＰＮ’ｓ 体系网络的组成、配比、交联剂品种及用量等因素对体系相容性及阻尼性能的影响。结果表明：上述诸因素对多组分乳胶ＩＰＮ′ｓ 体系的相容性及阻尼性能均有较明显影响; 适当选择各网络的组成及配比、交联剂品种及用量,可得到综合性能优良的多组分乳胶ＩＰＮ′ｓ。     

胶乳型互穿聚合物网络(LIPN)阻尼材料

详细讨论了LIPN体系的阻尼原理。高分子材料在发生玻璃化转变时,大分子链段在玻璃化转变温度Tg附近的运动可以把振动能转化为热能耗散掉,借此可以达到减振、降噪的目的。这也是LIPN作为阻尼材料的依据。阻尼笥能是分子运动的结果,LIPN组分间的相容性及相互作用是影响阻尼性能的重要因素;采用不同的合成方法,将形成不同的微观形态,也会导致材料阻尼性能的差异。因此本文又深入探讨了各种合成参数及合成条件对体系性能的影响,并且指出了合成过程中特别需要注意的几个问题。     

多组分乳胶IPN‘s体系的相容性和阻尼性能

用动态粘弹谱仪研究多组分乳胶ＩＰＮ‘Ｓ体系网络的组成,配比,交联剂品种及用量等因素对体系相容性及阻尼的影响。结果表明：上述诸因素对多组分乳胶ＩＰＮ’ｓ体系的相容性及阻尼性能均有较明显影响;适当选择各网络的组成及配比,交联剂品种及用量,可得到综合性能优良的多组分乳胶ＩＰＮ’ｓ。     

聚丙烯酸酯/聚苯乙烯乳胶互穿聚合物网络阻尼性能的研究

聚丙烯酸酯／聚苯乙烯乳胶互穿聚合物网络阻尼性能的研究刘瑞瑛王静媛韩庆国李玉玮汤心颐（吉林大学化学系长春１３００２３）关键词互穿聚合物网络，聚丙烯酸酯，聚苯乙烯，阻尼性能，乳胶自１９６９年Ｓｐｅｒｌｉｎｇ和Ｆｒｉｓｃｈ分别发展了ＭｉｌａｒＩＰＮ的...     

聚苯乙烯/聚丙烯酸丁酯乳胶互穿聚合物网络的动态力学性能研究

<正> 互穿聚合物网络(IPN)是一种新型聚合物共混物.自Sperling在1969年合成聚丙烯酸乙酯/聚苯乙烯异步IPN(Sequential IPN)后,该领域进展很快.乳胶IPN(latex IPN)是用改进的乳液聚合法合成的一种微观互穿IPN.在前文中,我们报道了聚苯乙烯/聚丙烯酸丁酯(PS/PBA)乳胶IPN的合成,本文研究一些因素对PS/PBA乳胶IPN动态力学性能的影响.     

粘弹性阻尼材料中互穿聚合物网络技术的应用

阐述了粘弹性材料在振动波作用下的阻尼机理,指出声波法和模量法的统一性。综述了互穿聚合物网络技术要点,并解释相分离体系宽玻璃化转变区间的形成机理;介绍了互穿聚合和网络技术形成的新途径及梯度互穿聚合物网络技术要点。     

交联密度对聚硅氧烷/聚丙烯酸酯同步互穿聚合物网络阻尼材料性能的影响

阻尼性能;交联密度对聚硅氧烷/聚丙烯酸酯同步互穿聚合物网络阻尼材料性能的影响     

BaTiO3 / (PU/UP-IPNS)复合材料的相容性、力学性能和阻尼性能研究(英)

以水热法合成的BaTiO3纤维和同步法制备的互穿聚合物网络为原料，采用原位分散聚合法获得了一系列BaTiO3/(PU／UP-IPNs)复合材料。采用傅立叶交换红外分光光度计跟踪考察了IPNs的聚合过程，用透射电镜观测了IPNs及其复合物的形貌。结果表明，IPNs中两相相畴尺寸在纳米级范围内，在此基础上，实现了BaTiO3纤维状的复合。动态力学性能的检测结果表明，相较纯IPNs，复合材料的阻尼损耗模量和阻尼损耗因子值均有所提高，且在低温区均出现了肩峰。复合物的最大损耗因子值均大于0．4，在约50℃范围内，E’值提高100MPa。力学性能检测结果表明，IPNs中的连续相是决定材料力学性能的主要因素；有机／无机组分间混溶性的降低，使BaTiO3/IPNs复合材料的抗张强度和断裂伸长率均下降。     

聚酯-聚酯多嵌段共聚物的合成及其动态力学性能

聚酯-聚醚多嵌段共聚物的动态力学性能谱上有两个T_8,不宜做阻尼材料。本文报道聚对苯二甲酸乙二醇酯(PET)-端羟基聚己二酸乙二醇酯(PEA)共聚物(简称嵌段共聚酯),比聚醚-聚酯多嵌段共聚物有更好的相容性。我们研究了PEA的分子量,间苯二甲酸的用量对嵌段共聚酯的结晶度,以及结晶度对嵌段共聚酯的动态力学性能的影响。     

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的影响

采用同步法合成了聚氨酯／聚苯乙烯（ＰＵ／ＰＳ）互穿聚合物网络（ＩＰＮ）．通过改变ＮＣＯ／ＯＨ比、三元醇／二元醇（３ＯＨ／２ＯＨ）比、异氰酸酯类型、多元醇分子量、二乙烯基苯含量及丙烯酸β－羟乙酯的含量，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／ＰＳＩＰＮ体系，采用增加交联密度、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．     

Preparation and Characterization of Interpenetrating Polymer Hydrogels Based on Poly(acrylic acid) and Poly(vinyl alcohol)

Interpenetrating polymer hydrogels (IPHs) of Poly (vinyl alcohol) (PVA) and Poly (acrylic acid) (PAAc) have been prepared by a sequential method: crosslinked PAAc chains were formed in aqueous solution by crosslinking copolymerization of acrylic acid and N, N′-methylenebisacrylamide in the presence of PVA. The application of freezing-thawing cycles (F-T cycles) leads to the formation of a PVA hydrogel within the synthesized PAAc hydrogel. The swelling and the viscoelastic properties of the prepared IPHs were evaluated on the basis of the structural features obtained from solid state ¹³C-NMR spectroscopy.     

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。     

聚氨酯/乙烯基酯树脂互穿聚合物网络阻尼性能的研究

采用二步法制备了聚氨酯／乙烯基酯树脂互穿聚合物网络,动态力学分析法研究了ＩＰＮ的阻尼性能。结果表明,聚氨酯／乙烯基酯树脂互穿聚合物网络出现宽温度阻尼范围。当聚氨酯／乙烯基酯树脂＝４０／６０时,材料的宽温度范围的阻尼性能最好。在体系中引入柔性链可改善低温阻尼性能,而引入刚性链则降低阻尼值、提高阻尼温度、阻尼温度范围变窄。在体系中引入大侧基能显著提高聚氨酯／乙烯基酯树脂互穿聚合物网络的阻尼性能,提高交     

互穿网络高吸水树脂IPN的合成

采用溶液聚合制备了聚乙烯醇(PVA)和部分中和的丙烯酸-丙烯酰胺共聚物复合的互穿网络高吸水树脂(IPN)。通过正交实验研究了单体浓度,交联剂用量对IPN吸水率的影响。PVA的加入能有效提高IPN的吸水能力。在较适宜的反应条件下,IPN吸蒸馏水量达1481倍,吸0.9%NaCl溶液为130倍。     

聚氯甲基苯乙烯纳米乳胶粒子的制备

聚氯甲基苯乙烯纳米乳胶粒子的制备;聚氯甲基苯乙烯;纳米乳胶粒子;乳液聚合     

Grafting reactions of vinyl acetate onto poly[(vinyl alcohol)-co-(vinyl acetate)]

The grafting preference of vinyl acetate onto the methine carbon of poly(vinyl alcohol) (PVOH) versus the acetate group of poly(vinyl acetate) (PVAc) was determined as part of an attempt to prepare novel branched PVOH from partially hydrolyzed PVAc. The results showed long chain grafting on the acetate groups of the PVAc units rather than the methine carbons of the PVOH or PVAc units. Decreasing the monomer or initiator concentration decreased the molecular weight of the graft copolymer formed. Of the initiators studied, ammonium persulfate gave the largest increase in copolymer molecular weight. Both hydrolysis and reacetylation combined with gel permeation chromatography (GPC) and ¹³C-NMR of the fully hydrolyzed material were used to estimate the number and location of grafts. © 1996 John Wiley & Sons, Inc.     

Synthesis and Characterization of a Hydrophilic/Hydrophobic IPN Composed of Poly（vinyl alcohol） and Polystyrene

A hydrophilic/hydrophobic interpenetrating polymer network （IPN） of poly （vinyl alcohol） / polystyrene was prepared by conversion of the IPN of poly （vinyl acetate）/polystyrene. The hydrophilic/hydrophobic IPN was characterized by FT-IR and DSC, and the swelling ratios of the IPN in different solvents were measured.     

Photomechanical Switching Behavior of Semi‐Interpenetrating Polymer Network Consisting of Azobenzene‐Carrying Crosslinked Poly(vinyl ether) and Polycarbonate

Summary: A novel semi‐interpenetrating polymer network (semi‐IPN) with photomechanical switching ability was developed by a cationic copolymerization of azobenzene‐containing vinyl ethers in a matrix of a linear polycarbonate (PC). The semi‐IPN film showed reversible deformation upon switching the UV irradiation on and off and responded with unprecedented rapidity. The photomechanical effect is attributed to a reversible change between the highly aggregated and dissociated states of the azobenzene groups.

The reversible UV response of the length of the semi‐IPN film at 25 °C.     

Synthesis and Characterization of Poly(N-isopropylacrylamide) and Poly(vinyl acetate) Diblock Copolymers via MADIX Process

The synthesis of diblock copolymers of poly(N-isopropylacrylamide) (PNIPAM) and poly(vinyl acetate) (PVAc) was performed by macromolecular design via interchange of xanthates (MADIX) process. Following the preparation of methyl (isopropoxycarbonothioyl) sulfanyl acetate (MIPCTSA) as chain transfer agent, it was reacted with vinyl acetate to obtain PVAc macro-chain transfer agent. Then, block copolymerization was completed by successive addition of N-isopropylacrylamide (NIPAM). ¹H NMR spectroscopy confirmed the presence of both blocks in the copolymer structure, with the expected composition based on the feed ratio. Size Exclusion Chromatography (SEC) was used to investigate the relative values of molecular characteristics. Only 20% of PVAc was converted to block copolymer. The resultant block copolymer structures were further examined in terms of their morphologies as well as critical micelle concentration (CMC) by using ESEM and Fluorescence Excitation Spectroscopic techniques, respectively. Morphological characterization confirmed amphiphilic block copolymer formation with the existence of mainly ca. 100 nm well distributed micelles. The thermo responsive amphiphilic behavior of the block copolymer solutions were followed by Dynamic Light Scattering (DLS) technique.     

Thermal degradation of ethylene (vinyl acetate)

Ethylene (vinyl acetate), EVA, is a copolymer which is thermally degraded at high temperatures, with acetic acid release at approximately 620 K. This release can be studied by using thermal methods, and in particular thermogravimetric analysis.The present work was focused on establishing the polymer weight loss with temperature in order to calculate the activation energy of the overall deacetylation process. To obtain the final results, a Mettler TC50 instrument coupled with a Mettler TC11 microprocessor was used.The activation energies of four different industrial EVA formulations were calculated. The results obtained by applying different kinetic methods reported in the literature agreed reasonably well; they were compared in order to select the best method of reporting EVA deacetylation results.The authors wish to express their appreciation to DGICYT (Spain), Project AMB 94-107, for financial support of this study.