遥爪丁腈共聚物的增韧环氧－聚氨酯IPN及PVC共混物的合成与表征

Ⅰ. 增韧环氧／聚氨酯互穿网络聚合物的合成与表征 用部分环氧树脂与丁腈羧反应，进行端基转化，制得端环氧基丁腈－环氧共聚物与环氧树脂的混合物，经叔胺固化后，得到增韧环氧（TEpx）。制备了两种IPN体系，体系1为增韧环氧／蓖麻油聚氨酯IPN，体系2为增韧环氧／聚醚聚氨酯IPN。用红外光谱研究了动力学，研究结果是，对于体系1，－OH基与－NCO基的反应速度大于环氧基的聚合速度，因此，IPN体系中，PU网络的形成比环氧网络快。环氧上的－OH基与蓖麻油上的羟基相似。同属伸羟基，它也会与－NCO基反应，因此，所形成的IPN的两网络间，存在着一定程度的化学交联。在增韧环氧的分子结构中，含有丁腈羧低聚物链段，使得增韧环氧与蓖麻油聚氨酯的相容性较好，该因素对这种IPN形态结构的形成，是很重要的，从动态力学性能的测试结果，能说明这个问题，即玻璃化转变峰很宽，在一定组成时，半峰宽几乎达100 ℃。对于体系2，聚氨酯相起反应的羟基是伯羟基，它与－NCO基的反应速度比环氧中的羟基与－NCO基的反应速度大得多。此外，体系中的两组分，即增韧环氧与聚醚聚氨酯的相容性不好，反应速度的差别与相容性的差别，均将导致反应体系中相分离程度的增大。这在tanZ-T曲线上表现得很明显，出现了两个相距甚远的玻璃化转变峰。利用透射电子显微镜对两个IPN体系进行了形态观察，这些IPN具有特殊的结构，既有增韧环氧所存在的两相结构，又有IPN的两相结构。Ⅱ. 聚氯乙烯－丁腈羟低聚物共混物的合成与表征 制备了高聚物（PVC）－低聚物（HTBN）共混物，研究了该共混物的力学性能，阻尼性能及形态结构。研究结果表明，在HTBN中，丙烯腈含量较高时，随着HTBN加入量的增加，PVC的阻尼峰均有不同程度的加宽加高。在力学性能方面，共混物的抗张强度、伸长率也随低聚物中丙烯腈含量的高低而变化，丙烯腈含量较高时（25％，36％），随HTBN加入量的增加，性能变化不大，而丙烯腈含量较低时（15％，5％），当HTBN的加入达一定量时，性能发生突降。这些现象的出现，主要与相容性有关，HTBN中丙烯腈含量高，极性大，与PVC混溶性好，因而阻尼性能、力学性能均好。而HTBN中丙烯腈含量低，与PVC之间的粘合力不好，即混溶性不好，因而共混物性能不好。由TEM照片看，该共混体系的形态结构为细胞状结构，细胞内存在着界面模糊的两相结构，在低丙烯腈含量（15％）时，存在着部分界面清晰的两相结构，形态观察的结果与性能测定的结果一致。

Sulphonated Tetramethyl Poly(ether ether ketone)/Epoxy/Sulphonated Phenol Novolac Semi-IPN Membranes for Direct Methanol Fuel Cells

The sulphonated phenol novolac (PNBS) which was used as a curing agent of epoxy was synthesised from phenol novolac (PN) and 1,4-butane sultone and confirmed by FTIR and H-1 NMR. The degree of sulphonation (DS) in PNBS was calculated by H-1 NMR. The semi-IPN membranes composed of sulphonated tetramethyl poly(ether ether ketone) (STMPEEK) (the value of ion exchange capacity is 2.01 meq g(-1)), epoxy (TMBP) and PNBS were successfully prepared. The semi-IPN membranes showed high thermal properties which were measured by differential scanning calorimeter (DSC) and thermogravimetric analysis (TGA) With the introduction of the corss-linked TMBP/PNBS, the mechanical properties, dimensional stability, methanol resistance and oxidative stability of the membranes were improve in comparison to the pristine STMPEEK membrane.

聚环氧氯丙烷聚氨酯／聚苯乙烯IPN的玻璃化转变行为

用ＤＳＣ和动态弹粘谱（ＤＭＳ）研究了聚环氧氯丙烷聚氨酯／聚苯乙烯互穿聚合物网络［ＰＵ（ＰＥＣＨ）／ＰＳＩＰＮ］的玻璃化转变行为发现，当ＩＰＮ中聚苯乙烯（ＰＳ）含量大于２０％（质量分数）时，ＩＰＮ是不相容体系，有两个玻璃化转变ＰＳ交链度的增加，对应于ＰＵ的玻璃化转变（ＴｇⅠ）不变，对应于ＰＳ的玻璃化转变（ＴｇⅡ）向高温方向移动，转变越来越不明显，加入氨酯反应催化剂时，Ｔｇ明显内移，ＴｇⅡ内移超过２０℃，相容性增加。

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。

PU软段结构对PU／PMMA IPN中两组分相容性的影响

用同步法合成了４种聚氨酯／聚甲基两烯酸甲酯互穿聚合物网络（ＰＵ／ＰＭＭＡＩＰＮ），利用ＤＤＣ、ＴＥＭ和动态力学谱（ＤＭＳ）等手段综合研究了ＩＰＮ中两组分的相容性和相态结构，用基团贡献加和方法计算了各种ＰＵ和ＰＭＭＡ的溶度参数δ，结合ＰＵ软段链结构讨论了各种ＩＰＮ呈现不同相容性和相态结构的原因。

聚环氧氯丙烷聚氨酯／聚甲基丙烯酸甲酯IPN力学性能

利用改变组成比、聚氨酯ＰＵ软段（端羟基聚环氧氯丙烷）的分子量、Ｒ值（ＮＣＯ／ＯＨ）、异氰酸酯和两网络各自交联剂含量合成出５个系列的聚环氧氯丙烷聚氨酯／聚甲基丙烯酸甲酯互穿聚合物网络（ＰＵ／ＰＭＭＡＩＰＮ），利用ＩＰＮ中交联、互穿、缠结程度的不同，并结合ＤＳＣ、ＴＥＭ、动态粘弹谱讨论了ＩＰＮ力学性能。

互穿聚合物网络（IPN）形成过程的动力学研究进展

本文评述了目前在互穿聚合物网络（ＩＰＮ）形成过程的动力学研究方面所取得的成果和存在的不足。认为ＦＴ－ＩＲ是一研究复杂的ＩＰＮ体系动力学的有效手段。阐述了几种ＩＰＮ体系的形成动力学行为及其特点。

CSM/PBMA/EP三组分IPN形态及性能研究

本文用同步-分步结合的方法合成了氯磺化聚乙烯/聚甲基丙烯酸丁酯/环氧树脂(CSM/PBMA/EP)三组分IPN,对其形态及性能进行了研究。结果表明:随组成比的改变可以得到相容性不同的IPN,当CSM/PBMA/EP=40/40/20时,在动态力学谱上出现一个加宽的T_g转变峰;EP含量为9％时,得到相容性比较好的IPN。用分步染色的方法不仅可以观察三组分IPN的相区尺寸变化,也可以了解三相的相容程度。

增韧环氧树脂/蓖麻油聚氨酯IPN的性能研究

研究了端羧基丁二烯-丙烯腈共聚物增韧环氧树脂(TER)与蓖麻油聚氨酯(PU)组成的互穿聚合物网络(IPN)的应力-应变行为、密度和溶胀行为。结果表明,在TER嵌段共聚物/PU(质量比)值为某一定值时,IPN表现出补强弹性体行为,它既有较高的强度,又有很高的伸长率,断裂能也达到最大值;IPN的密度高于按共混物加合法则计算的值,溶胀度则低于计算值,说明网络间存在着互穿。

Desenvolvimento de redes de polímeros interpenetrantes (IPN) para a aplicação como eletrólito polimérico

Uma nova rede de polímeros interpenetrantes (IPN) baseada em poliuretana de óleo de mamona e poli(etileno glicol) e poli(metacrilato de metila) foi preparada para ser utilizada como eletrólito polimérico. Os seguintes parâmetros de polimerização foram avaliados: massa molecular do poli(etileno glicol) (PEG), concentração de PEG e concentração de metacrilato de metila. As membranas de IPN foram caracterizadas por calorimetria diferencial de varredura (DSC) e espectroscopia de infravermelho por transformada de Fourier (FT-IR). Os eletrólitos de redes de polímeros interpenetrantes (IPNE) foram preparados a partir da dopagem com sal de lítio através do inchamento numa solução de 10% em massa de LiClO4 na mistura de carbonato de etileno e carbonato de propileno na razão mássica de 50:50. As IPNEs foram caracterizadas por espectroscopia de impedância eletroquímica e Raman. As IPNEs foram testadas como eletrólito polimérico em supercapacitores. As células capacitivas foram preparadas utilizando eletrodos de polipirrol (PPy). Os valores de capacitância e eficiência foram calculados por impedância eletroquímica, voltametria cíclica e ciclos galvonostáticos de carga e descarga. Os valores de capacitância obtidos foram em torno de 90 F.g-1 e eficiência variou no intervalo de 88 a 99%. Os valores de densidade de potência foram superiores a 250 W.kg-1 enquanto que a densidade de energia variou de 10 a 33 W.h.kg-1, dependendo da composição da IPNE. As características eletroquímicas do eletrólito formado pela IPN-LiClO4 (IPNE) foram comparadas aos eletrólitos poliméricos convencionais, tais como poli(difluoreto de vinilideno)-(hexafluorpropileno) ((PVDF-HFP/LiClO4) e poliuretana comercial (Bayer desmopan 385) (PU385/LiClO4). As condutividades na temperatura ambiente foram da ordem de 10-3 S.cm-1. A capacitância da célula utilizando eletrodos de PPy com eletrólito de PVDFHFP foi de 115 F.g-1 (30 mF.cm-2) e 110 F.g-1 (25 mF.cm-2) para a célula com PU385 comparadas a 90 F.g-1 (20 mF.cm-2) para a IPNE. Os capacitores preparados com eletrólito de IPNE apresentaram valores de capacitância inferior aos demais, entretanto provaram ser mais estáveis e mais resistentes aos ciclos de carga/descarga. A interpenetração de duas redes poliméricas, PU e PMMA produziu um eletrólito com boa estabilidade mecânica e elétrica. Um protótipo de supercapacitor de estado sólido foi produzindo utilizando eletrodos impressos de carbono ativado (PCE) e o eletrólito polimérico de IPNE. A técnica de impressão de carbono possui várias vantagens em relação aos outros métodos de manufatura de eletrodos de carbono, pois a área do eletrodo, espessura e composição são variáveis que podem ser controladas experimentalmente. As células apresentaram uma larga janela eletroquímica (4V) e valores da capacitância da ordem de 113 mF.cm-2 (16 F.g-1). Métodos alternativos de preparação do PCE investigados incluem o uso de IPNE como polímero de ligação ao carbono ativado, estes eletrodos apresentaram valores de capacitância similares aos produzidos com PVDF. A influência do número de camadas de carbono usadas na produção do PCE também foi alvo de estudo. Em relação ao eletrólito polimérico, o plastificante e o sal de lítio foram adicionados durante a síntese, formando a IPNGel. As células apresentaram alta capacitância e boa estabilidade após 4000 ciclos de carga e descarga. As membranas de IPN foram testadas também como reservatório de medicamento em sistemas de transporte transdérmico por iontoforese. Os filmes, mecanicamente estáveis, formaram géis quando inchado em soluções saturadas de lidocaina.HCl, anestésico local, em propileno glicol (PG), poli(etileno glicol) (PEG400) e suas misturas. O grau de inchamento em PG foi de 15% e 35% em PEG400. Agentes químicos de penetração foram utilizados para diminuir a resistência da barreira causada pela pele, dentre eles o próprio PG, a 2-pirrolidinona (E1) e a 1-dodecil-2-pirrolidinona (E2). Os géis foram caracterizados por espectroscopia de impedância eletroquímica e transporte passivo e por iontoforese através de uma membrana artificial (celofane). O sistema IPN/ lidocaina.HCl apresentou uma correlação linear entre medicamento liberado e a corrente aplicada. Os melhores resultados de transporte de medicamento foram obtidos utilizando o PG como solvente.

Investigation of electrophoretic loading and enhanced mechanical properties of hydrogels for delivery of therapeutic proteins

Hydrogels, which are three-dimensional crosslinked hydrophilic polymers, have been used and studied widely as vehicles for drug delivery due to their good biocompatibility. Traditional methods to load therapeutic proteins into hydrogels have some disadvantages. Biological activity of drugs or proteins can be compromised during polymerization process or the process of loading protein can be really timeconsuming. Therefore, different loading methods have been investigated. Based on the theory of electrophoresis, an electrochemical gradient can be used to transport proteins into hydrogels. Therefore, an electrophoretic method was used to load protein in this study. Chemically and radiation crosslinked polyacrylamide was used to set up the model to load protein electrophoretically into hydrogels. Different methods to prepare the polymers have been studied and have shown the effect of the crosslinker (bisacrylamide) concentration on the protein loading and release behaviour. The mechanism of protein release from the hydrogels was anomalous diffusion (i.e. the process was non-Fickian). The UV-Vis spectra of proteins before and after reduction show that the bioactivities of proteins after release from hydrogel were maintained. Due to the concern of cytotoxicity of residual monomer in polyacrylamide, poly(2-hydroxyethyl- methacrylate) (pHEMA) was used as the second tested material. In order to control the pore size, a polyethylene glycol (PEG) porogen was introduced to the pHEMA. The hydrogel disintegrated after immersion in water indicating that the swelling forces exceeded the strength of the material. In order to understand the cause of the disintegration, several different conditions of crosslinker concentration and preparation method were studied. However, the disintegration of the hydrogel still occurred after immersion in water principally due to osmotic forces. A hydrogel suitable for drug delivery needs to be biocompatible and also robust. Therefore, an approach to improving the mechanical properties of the porogen-containing pHEMA hydrogel by introduction of an inter-penetrating network (IPN) into the hydrogel system has been researched. A double network was formed by the introduction of further HEMA solution into the system by both electrophoresis and slow diffusion. Raman spectroscopy was used to observe the diffusion of HEMA into the hydrogel prior to further crosslinking by ã-irradiation. The protein loading and release behaviour from the hydrogel showing enhanced mechanical property was also studied. Biocompatibility is a very important factor for the biomedical application of hydrogels. Different hydrogels have been studied on both a three-dimensional HSE model and a HSE wound model for their biocompatibilities. They did not show any detrimental effect to the keratinocyte cells. From the results reported above, these hydrogels show good biocompatibility in both models. Due to the advantage of the hydrogels such as the ability to absorb and deliver protein or drugs, they have potential to be used as topical materials for wound healing or other biomedical applications.

Toughness and toughening mechanisms of porous thin films

Toughness is the ability of a material to deform plastically and to absorb energy before fracture. The first of its kind, this book covers the most recent developments in the toughening of hard coatings and the methodologies for measuring the toughness of thin films and coatings. The book looks at the present status of toughness for coatings and discusses high-temperature nanocomposite coatings, porous thin films, laser treated surface layers, cracking resistance, indentation techniques, sliding contact fracture, IPN hybrid composites for protection, and adhesion strength.