乙二醇二缩水甘油醚的合成及作为阳离子型紫外光固化稀释剂性能研究

以三氟化硼乙醚络合物为催化剂,以氢氧化钠为成环反应的闭环剂,利用乙二醇和环氧氯丙烷为原料合成了乙二醇二缩水甘油醚.研究了催化剂三氟化硼乙醚络合物用量、环氧氯丙烷和乙二醇摩尔比、氢氧化钠和乙二醇摩尔比,以及成环反应温度这些因素对合成反应的影响.结果表明较好的合成反应条件是:三氟化硼乙醚络合物质量分数为0.40%,环氧氯丙烷和乙二醇较佳摩尔比为2.4:1,氢氧化钠和乙二醇较佳摩尔比为2.2:1,较佳的成环反应温度为30℃.同时,把乙二醇二缩水甘油醚作为稀释剂加入到环氧树脂E-51中,利用三芳基锍鎓六氟锑酸盐作为引发剂,制备了阳离子型紫外光固化涂料,其紫外光固化膜的拉伸强度为46.25MPa,杨氏模量为1487.26MPa,断裂伸长率为6.27%.     

端环氧基聚苯乙烯低聚的物合成与表征

采用阴离子聚合法,以正丁基锂(n-BuLi)为引发剂、乙二醇二缩水甘油醚(EGDE)为封端剂,在常压惰性气体保护下引发苯乙烯(St)聚合,制得端环氧基聚苯乙烯低聚物(PS-ep)。采用GPCI、R和1H-NMR对PS-ep进行表征,并用盐酸-二氧六环银量法测定端环氧基含量。结果表明:以EGDE为封端剂可以使端环氧基摩尔分数(xep)达到0.80左右;升高封端反应温度和延长封端反应时间有利于提高端环氧基的摩尔分数;EGDE与n-BuLi的摩尔比以4∶1为宜。     

渗透型改性环氧灌浆材料

以环氧树脂为主剂、脂肪族多胺为固化剂,以糠酮树脂、活性稀释剂糠醛丙酮、硅烷、Mannich型酚醛胺为主要改性材料的改性环氧灌浆材料,具有优异的渗透性,结合适当的施工工艺,可获得固化时间可调、固化物强度符合实际工程的渗透型改性环氧灌浆材料,并可用作多种用途。     

活性稀释剂苄基缩水甘油醚丙烯酸酯的合成及性能表征

本文以苄基缩水甘油醚和丙烯酸为原料合成活性稀释剂苄基缩水甘油醚丙烯酸酯(BGEA),研究了反应温度、催化剂和阻聚剂用量对反应的影响.结果表明最佳的反应条件为:反应温度110℃左右,催化剂N,N’-二甲基苄胺质量分数为0.9%,阻聚剂对甲氧基苯酚质量分数为0.2%.后将BGEA作为稀释剂加入到双酚A型环氧丙烯酸树脂中配制成光固化涂料,利用TG、AFM等表征手段对光固化膜的热性能、表面形貌及物理机械性能进行研究.     

GAP黏合剂体系交联网络结构研究

为改善聚叠氮缩水甘油醚(GAP)黏合剂体系的网络结构,分别考察了GAP与二官能度的甲苯二异氰酸酯(TDI)或异佛尔酮二异氰酸酯(IPDI)预聚、缩二脲多异氰酸酯(N-100)与二官能度固化剂的种类和配比对GAP弹性体力学性能、网络结构参数、网络结构完整性以及拉伸断面形貌的影响.结果表明,将GAP与TDI预聚可提高体系交联网络结构的完整性,同时提高弹性体的断裂延伸率和最大拉伸强度.适量加入二官能度异氰酸酯能改善体系的网络结构完整性,由于预聚体中TDI与IPDI结构和反应活性的差别,GAP/TDI/N-100弹性体在N-100与TDI质量比为7∶3时体系网络结构最完整,而GAP/IPDI/N-100弹性体在N-100与IPDI质量比为5∶5时体系网络结构最完整;在相同的N-100含量下GAP/IPDI/N-100体系比GAP/TDI/N-100体系强度高,延伸率略低.随着N-100含量的减少,GAP/TDI/N-100体系最大拉伸强度(δ_m)从0.66 MPa降低到0.32 MPa,断裂延伸率(ε_b)从104.6%提高到506.3%;GAP/IPDI/N-100体系强度在W(N-100)∶W(IPDI)=7∶3时达到最大值0.69 MPa,断裂延伸率从103.2%提高到391.4%.扫描电镜(SEM)结果表明,弹性体的拉伸断面形貌与弹性体的网络结构完整性和力学性能具有良好的对应关系.     

光引发阳离子聚合反应的研究Ⅲ．硫鎓盐BDS引发环氧化合物光聚合的DSC研究

用改装的国产CDR-1型DSC仪研究了苯基缩水甘油醚(PGE)和环氧树脂(E-51)以双-[4-(二苯硫基)苯基)硫-二-六氟化磷引发的光聚合。研究了引发剂浓度、光强、温度等因素对聚合反应的影响,对于PGE,聚合速率与引发剂浓度的0.90次方、与光强的0.78次方成比例,对于E-51,聚合速率与引发剂浓度的0.87次方成比例,而与光强的关系则比较复杂,温度分别超过70℃(对PGE)或80℃(对E-51)后,对提高聚合反应速率的作用已不明显。作为活性稀释剂,PGE可以较大地提高E-51的聚合速率。     

聚环氧磺羧酸的合成及其阻垢性能

聚环氧磺羧酸的合成及其阻垢性能;聚环氧磺羧酸; 聚环氧琥珀酸; 阻垢剂     

聚乳酸扩链及热性能研究

采用L-乳酸熔融缩聚,制备了粘均相对分子质量较低的聚乳酸,并以亚磷酸三苯酯和1,4-丁二醇二缩水甘油醚为扩链剂对其扩链。亚磷酸三苯酯和1,4-丁二醇二缩水甘油醚可以有效提高聚乳酸的粘均相对分子质量,但是,扩链产物PLLA-TPPi和PLLA-BDDE的粘均相对分子质量未随亚磷酸三苯酯和1,4-丁二醇二缩水甘油醚的用量呈线性变化,而是表现为一峰值。PLLA-TPPi和PLLA-BDDE的玻璃化温度均随扩链产物的粘均相对分子质量的增大而提高;与PLLA-BDDE相比,PLLA-TPPi链中的TPPi结构更能有效促进PLLA链的结晶。     

盐酸阿米替林/海藻酸钠/壳聚糖微球的制备及释放性能

盐酸阿米替林;海藻酸钠;壳聚糖;微球;交联;乙二醇二缩水甘油醚     

含改性松香的丁二醇二缩水甘油醚固化反应动力学研究

设计了含改性松香无苯环的环氧固化体系和无松香的对照体系,分别是无松香体系Ⅰ：丁二醇二缩水甘油醚（BDGE）和甲基六氢苯酐（MeHHPA）;无规体系Ⅱ：丙烯酸松香（AR）、BDGE和MeHHPA;有规体系Ⅲ：丙烯酸松香基环氧树脂（ARE,由AR和BDGE预聚而来）和MeHHPA。对三体系的固化反应应用动态示差扫描量热仪（DSC）进行了研究,利用KAS法求得不同转化率下的表观活化能,通过整个反应过程反应活化能的变化,得到了三体系反应的内在机理,结果发现松香基的引入及引入顺序都对固化反应产生影响。     

Influence of the Epoxy/Acid Stoichiometry on the Cure Behavior and Mechanical Properties of Epoxy Vitrimers

Bisphenol A epoxy resin cured with a mixture of dimerized and trimerized fatty acids is the first epoxy vitrimer and has been extensively studied. However, the cure behavior and thermal and mechanical properties of this epoxy vitrimer depend on the epoxy/acid stoichiometry. To address these issues, epoxy vitrimers with three epoxy/acid stoichiometries (9:11, 1:1 and 11:9) were prepared and recycled four times. Differential scanning calorimetry (DSC) was used to study the cure behavior of the original epoxy vitrimers. The dynamic mechanical properties and mechanical performance of the original and recycled epoxy vitrimers were investigated by using dynamic mechanical analysis (DMA) and a universal testing machine. Furthermore, the reaction mechanism of epoxy vitrimer with different epoxy/acid stoichiometry was interpreted. With an increase in the epoxy/acid ratio, the reaction rate, swelling ratio, glass transition temperature and mechanical properties of the original epoxy vitrimers decreased, whereas the gel content increased. The recycling decreased the swelling ratio and elongation at break of the original epoxy vitrimers. Moreover, the elongation at break of the recycled epoxy vitrimers decreased with the epoxy/acid ratio at the same recycling time. However, the gel content, tensile strength and toughness of the original epoxy vitrimers increased after the recycling. The mechanical properties of epoxy vitrimers can be tuned with the variation in the epoxy/acid stoichiometry.     

Mechanical Properties of Gel-Derived Materials

The mechanical behaviour of xerogels and aerogels is generally described in terms of brittle and elastic materials, like glasses or ceramics. The main difference compared to silica glass is the order of magnitude of the elastic and rupture moduli which are 10⁴ times lower. However, if this analogy is pertinent when gels are under a tension stress (bending test) they exhibit a more complicated response when the structure is submitted to a compressive stress. The network is linearly elastic under small strains, then exhibits yield followed by densification and plastic hardening. As a consequence of the plastic shrinkage it is possible to densify and stiffen the gel at room temperature. These opposite behaviours (elastic and plastic) are surprisingly related to the same two kinds of gel features: the silanol content and the pore volume. Both elastic modulus and plastic shrinkage depend strongly on the volume fraction of pores and on the condensation reaction between silanols. On the mechanical point of view (rupture modulus and toughness), it is shown that pores and silanols play also an important role. Pores can be considered as flaws in the terms of fracture mechanics and the flaw size, calculated from rupture strength and toughness is related to the pore size distribution. Different kinds of gels structure (fractal or not fractal) have been synthesized by a control of the different steps of transformation such as sintering and plastic compaction. The relationships between structural and the elastic properties are discussed in terms of the percolation theory and fractal structure.     

HIPS／PP熔融反应共混及其动态力学性质

研究了高抗冲聚苯乙烯（HIPS）／聚丙烯（PP）共混物在过氧化二异丙苯（DCP）存在下的熔融反应过程及其动态力学性质．HIPS在DCP存在下以聚苯乙烯（PS）的降解为主，伴随着聚丁二烯（PB）的交联和接枝，PP在DCP存在下以降解为主，HIPS／PP在DCP存在下以PP同HIPS的反应接枝为主，这种原位生成的增容剂显著地改善了HIPS／PP两组份间的相容性，其分子运动特征较前两者发生明显变化，PS的Tg下降，PB和PP的Tg升高．     

聚离子液体修饰碳纳米管及其对环氧树脂力学性能的影响

为改善多壁碳纳米管(MWCNTs)在环氧树脂(EP)中的分散性和界面性质,以1-乙烯基-3-丁基咪唑六氟磷酸盐([VBIM]PF6)为单体合成聚离子液体(PIL),用于MWCNTs的表面改性.用热重分析(TG),拉曼光谱(Raman)和扫描电镜(SEM)对改性碳纳米管(PIL-CNTs)进行了表征.结果表明,PIL可吸附在MWCNTs表面且不改变MWCNTs的电子结构.与原始MWCNTs相比,PIL-CNTs在丙酮中的分散性更好.在EP中加入0.5 wt%的PIL-CNTs,以4,4'-二氨基二苯甲烷(DDM)为固化剂制备环氧树脂固化物.动态力学(DMA)研究表明,PIL-CNTs提高了EP的储能模量,玻璃化温度比纯EP和MWCNTs/EP分别提高了5.6℃和3.3℃;PILCNTs/EP的拉伸强度,弯曲强度和冲击强度较纯EP分别提高了35.2%,26.4%和45.0%.拉伸断面的SEM可看出PIL-CNTs在复合材料中的分散性和与环氧树脂基体的界面结合力均优于原始MWCNTs.     

On the Mechanical Properties of Popgraphene-Based Nanotubes: a Reactive Molecular Dynamics Study

Carbon-based tubular materials have sparked a great interest in future electronics and optoelectronics device applications. In this work, we computationally studied the mechanical properties of nanotubes generated from popgraphene (PopNTs). Popgraphene is a 2D carbon allotrope composed of 5-8-5 rings. We carried out fully atomistic reactive (ReaxFF) molecular dynamics for PopNTs of different chiralities ( and ) and/or diameters and at different temperatures (from 300 up to 1200 K). Results showed that the tubes are thermally stable (at least up to 1200 K). All tubes presented stress/strain curves with a quasi-linear behavior followed by an abrupt drop of stress values. Interestingly, armchair-like PopNTs ( ) can stand a higher strain load before fracturing when contrasted to the zigzag-like ones ( ). Moreover, it was obtained that Young's modulus (Y_Mod) (750–900 GPa) and ultimate strength (σ_US) (120–150 GPa) values are similar to the ones reported for conventional armchair and zigzag carbon nanotubes. Y_Mod values obtained for PopNTs are not significantly temperature-dependent. While the σ_US values for the showed a quasi-linear dependence with the temperature, the exhibited no clear trends.     

环氧／环氧丙烯酸酯的光交联和动态力学性能

用硬度法研究了环氧／环氧丙烯酸酯混杂体系中以硫翁盐引发光交联时，组成对光交联的影响；安息香二甲醚能促进混杂体系的光交联；动态力学性能的测定表明该体系是一相容性互网络体系；组成对体系的相容性，交联密度、互穿程度均有影响。     

Influence of Proteins on the Mechanical Properties of Agro-Based Materials

Summary : A new biodegradable thermoplastic material based on a wheat flour by-product has been developed. The influence of protein content in wheat flour on the mechanical properties of the material has been investigated. For protein content between 4% and 10%, no influence of the protein content was evidenced, whereas beyond 10% w/w of proteins in the wheat flour, the mechanical properties of agro-based materials decrease, thus confirming the advantage of using a wheat flour by-product (i.e. with protein content below 8% w/w).     

Effect of Aging on the Mechanical Properties of Polymeric Materials

Abstract

Aging can modify polymer structure at the molecular, macromolecular, and/or the morphological level and thus induce changes in the mechanical properties. Stiffness is generally not modified for nonrubbery materials, except for mass transfer (solvent plasticization or plasticizer loss) in amorphous polymers or phase transfer (crystallization or crystal destruction) in semicrystalline polymers. The most significant modulus changes occur in the radiochemical aging of semicrystalline polymers whose amorphous phase is in the rubbery state. Yield properties generally vary in the same way as stiffness. Physical aging at T < T _g can lead to a significant increase in the yield stress. Very general features can be observed for rupture properties, for instance: 1) Only ultimate elongation ε is a pertinent variable in kinetic studies of aging involving tensile testing and related methods, 2) the amplitude of ε variation for a given degradation conversion is considerably higher for initially ductile materials than for brittle ones, and 3) the rupture envelope σ = f(ε), i.e., the ultimate stress, is often very close to the initial tensile curve except for rubbery materials undergoing predominant crosslinking. The mechanisms of ultimate property changes are reviewed. A kinetic approach is proposed for the very important case of heterogeneous, diffusion-controlled aging.     

YDS系列化灌材料的耐老化性能

对YDS浆材固砂体进行了自然曝晒、中温浸泡水、人工加速热老化及耐化学介质腐蚀的试验,各项测试结果表明：YDS灌浆材料耐老化性能优良。文章还介绍了国内外应用环氧浆材的一些水工工程耐久性的调查结果。