多功能稀土促进剂(La-GDTC)的制备及其硫化性能研究

通过谷氨酸、二硫化碳和氯化镧合成了一种新型的多功能硫化促进剂——谷氨酸二硫代氨基甲酸镧(La-GDTC),利用紫外-可见吸收光谱、核磁共振13C谱、元素分析、红外光谱(FTIR)和X射线光电子能谱(XPS)等分析手段证实了La-GDTC中的二硫代氨基甲酸根和羧酸根与镧离子形成了配位络合结构。通过研究SBR/La-GDTC混炼胶的硫化性能,结果显示随着La-GDTC加入量的增多,SBR/La-GDTC混炼胶的正硫化时间(tc90)从17.23 min减少至12.47 min,证实了La-GDTC的加入能够很好地促进橡胶的硫化,这与SBR/La-GDTC混炼胶的活化能计算结果是一致的。     

SiO2表面RAFT接枝聚合苯乙烯

基于纳米SiO2表面羟基与7-甲基丙烯酰氧基丙基三甲氧基硅烷间的偶联反应,在纳米SiO2表面引入可聚合双键。采用可逆加成断裂链转移（RAFT）聚合技术,以偶氮二异丁腈为引发剂,使SiO2表面接枝聚合苯乙烯。考察了二硫代苯甲酸异丁腈酯、二硫代苯甲酸苄酯、（1,2,4-三氮唑）基二硫代甲酸苄酯和二硫代新戊酸苄酯等对SiO2表面接枝聚合苯乙烯速率的影响。结果表明,SiO2表面接枝聚合苯乙烯的速率决定于RAFT试剂的Z基团结构。二硫代新戊酸苄酯调控的SiO2表面接枝聚合苯乙烯的速率最高。     

具有高效抗真菌活性的β-氨基酸聚合物

通过模拟带有正电荷和两亲性结构的天然宿主防御肽(HDPs)，采用β-氨基酸N-硫代羧基酸酐(β-NTA)开环聚合方法，将不同比例正电荷单体N(α)-Z-DL-2,3-二氨基丙酸N-硫代羧基酸酐(DAP)和疏水性单体3-氨基-2-(苯基)丙酸N-硫代羧基酸酐(Ph)进行共聚，得到了系列两亲性β-氨基酸聚合物(DAP_xPh_y)₂₀。通过核磁共振氢谱仪(¹H-NMR)和凝胶渗透色谱仪(GPC)对其链长和结构进行表征。结果表明：(DAPx Phy)20聚合物具有高抗白色念珠菌活性，最低抑菌浓度(MIC)为1.56～12.5μg/mL，且该聚合物在200μg/mL质量浓度下未对人血红细胞和成纤维细胞造成明显毒性。     

重金属吸附剂二硫代羧基化玉米秸秆的制备

以玉米秸秆(CS)、二硫化碳、氢氧化钠为原料,制备出二硫代羧基化玉米秸秆(DTCS)。考察了DTCS制备过程的影响因素,确定了DTCS的制备条件。结果表明:在秸秆粒径10目(2.0 mm)、浸泡时间45 min、CS/CS_2/NaOH质量比1∶1∶2、预反应温度25℃、预反应时间30 min、主反应温度40℃、主反应时间1 h的条件下制备的DTCS对Cd(Ⅱ)的去除效果最好,Cd(Ⅱ)的最高去除率可达100%。DTCS的红外分析结果表明,CS分子链中成功引入了二硫代羧基。     

N,N-双(二硫代羧基)二乙烯三胺乙基聚合物的合成及其吸附性能

以二乙烯三胺与二硫化碳反应生成中间体[N,N-双(二硫代羧基)二乙烯三胺],进而与1,2-二氯乙烷聚合生成N,N-双(二硫代羧基)二乙烯三胺乙基聚合物,用红外光谱确认了中间体和聚合物的结构.测定了聚合物对一部分重金属离子的吸附性能.结果表明,聚合物能定量地吸附某些重金属离子,对Ag+、Cu2+等离子有较高的吸附容量.     

长链超支化聚酯改性纳米SiO_2及其在丁苯橡胶中的应用

利用二乙醇胺和丙烯酸甲酯合成的N,N-二羟乙基-3-胺基丙酸甲酯作为AB2型单体,以纳米SiO_2为核,通过其表面羟基与单体的反应,制得SiO_2接枝超支化聚酯的纳米粒子(SiO_2-HBP);再利用超支化端羟基与α-己内酯进行开环反应,合成了含柔性长链的二氧化硅-长链超支化聚酯杂化物(SiO_2-HBP-L);然后将杂化物与丁苯橡胶共混,制备了SiO_2-HBP-L/SBR纳米复合材料.FTIR、XPS和TGA测试证实改性后纳米SiO_2表面接枝了含长链超支化聚酯.SEM测试结果表明,相对于未改性的纳米SiO_2,SiO_2-HBP-L在乙醇和橡胶基体中分散性较好,且改性后纳米SiO_2与复合材料的相容性明显提高.硫化性能测试表明,SiO_2-HBP-L能大大缩短胶料的正硫化时间,增大总交联密度;同时SiO_2-HBP-L/SBR纳米复合材料的力学性能和耐磨性能有较大的提高,很好地实现了补强.     

硫化温度对绿色轮胎胎面胶结构与性能的影响

在轮胎的加工和制备过程中,硫化温度是影响橡胶复合材料网络结构和物理机械性能的重要因素之一.本文研究了硫化温度(140、150、160、170和180℃)对溶聚丁苯橡胶(SSBR)/顺丁橡胶(BR)(未填充体系)及SSBR/BR/白炭黑(Si O2)(填充体系)纳米复合材料的结构和物理机械性能的影响.结果表明:随硫化温度的升高,填充与未填充SSBR/BR混炼胶的硫化速率指数(CRI)升高,焦烧时间与工艺正硫化时间缩短;随硫化温度的升高,未填充SSBR/BR硫化胶的交联密度逐渐降低,同时拉伸强度、硬度、回弹、伸张疲劳性能随交联密度降低而降低.随硫化温度的升高,填充SSBR/BR硫化胶的交联密度先增大,在180℃时降低;多硫交联键含量逐渐降低,单硫与双硫交联键含量增加,填料分散性能逐渐变差.网络结构的变化使填充SSBR/BR硫化胶拉伸强度、断裂伸长率和生热降低,耐磨性、滚动阻力和耐湿滑性逐渐提高.     

原位制备PEI/SiO2复合材料及其改性环氧树脂的研究

在N,N-二甲基乙酰胺/四氢呋喃(DMAc/THF)混合溶剂中,在正硅酸乙酯(TEOS)存在条件下,通过溶胶-凝胶法原位制备了聚醚酰亚胺(PEI)/SiO2复合材料.在该复合材料中,当SiO2含量低于20 wt％时,透射电镜(TEM)和扫描电镜(SEM)的观察表明,SiO2纳米粒子可以均匀分散,粒径可在80～300 n...     

1,4-双-(二硫代羧基)哌嗪乙基聚合物的合成及其吸附性能

固相合成;1;4-双-(二硫代羧基)哌嗪乙基聚合物的合成及其吸附性能     

氟代位置对苝酰亚胺聚集态结构和电子传输性能的影响

合成了三种新型的有机电子受体: N,N'-二(2-氟代苯基)-3,4,9,10-苝四羧基二酰亚胺(D2MFPP)、N,N'-二(3-氟代苯基)-3,4,9,10-苝四羧基二酰亚胺(D3MFPP)和N,N'-二(4-氟代苯基)-3,4,9,10-苝四羧基二酰亚胺(D4MFPP). 利用元素分析、傅立叶变换红外(FTIR)等方法表征了它们的分子结构, 用紫外-可见光吸收光谱(UV-Vis)、X射线衍射(XRD)和原子力显微镜(AFM)等手段研究了氟代位置对苝酰亚胺薄膜聚集态结构的影响, 发现氟代使苝酰亚胺的聚集态发生变化, 且不同位置的氟代对其影响也不一样. 除了分子结构的影响, 外场条件也会产生很大的作用. 通过制备场效应晶体管研究了其电子传输性能, 发现氟代后器件的空气稳定性有明显提高.     

微波处理和溶胶凝胶法共同改性废胶粉及其与天然橡胶复合材料性能的研究

采用微波处理打断废胶粉(WRP)的三维网状结构用来提高WRP在有机溶剂中的溶胀性,然后采用溶胶凝胶法,将微波改性后的WRP浸入正硅酸乙酯中,通过水解反应和缩合反应,在WRP表面原位生成SiO2网络,从而制得改性废胶粉(MWRP).将制得MWRP与天然橡胶(NR)共混,制备了NR/MWRP复合材料,研究了NR/MWRP复合材料的性能.通过热重分析仪、差示扫描量热仪和力学分析表明微波处理最佳时间是20 s.由于微波处理提高了NR与WRP的相容性,原位生成的SiO2粒子起到了补强作用,所以所制备的NR/MWRP复合材料拥有较好的力学性能;随着Si69的加入,抑制了SiO2粒子聚集,提高了SiO2粒子的分散性,从而进一步提高复合材料的力学性能并降低复合材料的Payne效应;在进行频率扫描时,硫化胶的储存模量随频率的增大而增大;硫化胶的温度扫描结果表明,随着温度的升高,复合材料中SiO2粒子聚集程度加剧并且复合材料出现老化的现象.为了提高复合材料的耐老化性能,N,N-间苯撑双马来酰亚胺(BMI)作为一种防老剂加入复合材料中,BMI利用Diels-Aider反应补偿橡胶在老化过程中所损失的交联键并提高NR与WRP的界面相容性,从而提高复合材料的耐老化性能.     

聚醚型氨酯酰亚胺/二氧化硅杂化材料的合成与性能研究

利用Sol Gel共聚合反应制备出聚醚型氨酯酰亚胺 (PUI) /二氧化硅 (SiO2 )杂化材料 .利用NMR、FTIR、TG、DSC及SEM等测试手段对性能进行了基本表征 .FTIR研究结果发现在 10 0℃下能同时完成有机相PUI的亚胺化和无机相SiO2 凝胶网络的Sol Gel转变 .TG及SEM发现SiO2 含量为 9wt%时SiO2 聚集相粒径在 0 2～1 0 μm之间 ,耐热性明显提高并达到最佳 ;发现SiO2 含量的增加其颗粒粒径不断增大 ,并不断聚集成大粒径SiO2 相 ,有机和无机相分离明显 .DSC研究显示 ,SiO2 相的引入 ,对杂化材料聚醚软段富集相的Tg 不产生明显影响 .     

Thermal stability of styrene butadiene rubber (SBR) composites filled with kaolinite/silica hybrid filler

Styrene butadiene rubber (SBR) composites filled with fillers, such as modified kaolinite (MK), precipitated silica (PS), and the hybrid fillers containing MK and PS, were prepared by melt blending. The kaolinite sheets were finely dispersed in the SBR matrix around 20–80 nm in thickness and reached the nano-scale. The SBR composites with fillers exhibited excellent thermal stability compared to the pure SBR. The thermal stability of SBR composites was improved with the increasing of MK mass fraction. When MK hybridized with PS, kaolinite sheets were covered by the fine silica particles and the interface between filler particles and rubber matrix became more indistinct. SBR composite filled by hybrid fillers containing 40 phr MK and 10 phr PS became more difficult in decomposition and was better than that of 50 phr PS/SBR and 50 phr MK/SBR in thermal stability. Therefore, the hybridization of the fine silica particles with the kaolinite particles can effectively improve the thermal stability of SBR composites.     

两种不同粒径的SBR粒子对透明ABS树脂力学性能影响

从SBR橡胶粒子出发,采用乳液原位悬浮聚合方法合成了一系列透明ABS树脂.采用小粒径SBR橡胶粒子虽然可以获得透明性良好的透明ABS树脂,但树脂的抗冲性能较差.采用大粒径SBR橡胶粒子ABS树脂的透明性明显下降.采用由粒径分别为400nm和70nm两种SBR橡胶粒子所组成的双峰粒子(指粒度分布谱上有两个峰)体系,当二者比例在4/6~6/4范围内,总橡胶粒子含量为15%~18%时,所得到的透明ABS树脂冲击强度已经达到90~120J/m,透光率超过80%.初步探讨了不同增韧体系的ABS树脂的脆韧转变关系;研究了不同粒径橡胶粒子的协同增韧效应.确定了由SBR双峰粒子增韧体系获得具有良好力学和透光性能的ABS树脂的基本条件.     

Characterization of effects of thermal-oxidative aging on styrene-butadiene rubber/silica composites with vitamin C-lanthanum complex

A novel rubber antioxidant, vitamin C-lanthanum complex, was prepared and applied in styrene-butadiene rubber (SBR)/silica composites. The anti-aging behavior of SBR/silica composites with vitamin C-lanthanum complex was systematically investigated by mechanical property retention after aging, oxidation induction time, exothermic enthalpies of thermal oxidation, and thermo-oxidative degradation kinetics. The highlight of this work lies in the fact that several thermal analysis techniques were successfully applied to fully evaluate the thermal-oxidative aging of SBR/silica composites and the vitamin C-lanthanum complex was found to endow SBR/silica composites with better protection against aging than commercial antioxidants, which may be beneficial for better characterization of rubber aging and fruitful for the preparation of highly aging-resistant rubber composites, respectively.     

橡胶／纳米无机粒子增韧增强环氧树脂的研究

综述了当前环氧树脂增韧增强改性的研究现状,详细介绍了弹性体增韧环氧树脂、无机纳米粒子改性环氧树脂、粘土改性环氧树脂、纳米SiO2改性环氧树脂以及弹性体／无机纳米粒子协同增韧增强环氧树脂的机理和实验方法。并对其实验结果进行了分析比较。     

STUDY ON THE TOUGHENING MECHANISM OF RUBBER TOUGHENED EPOXY

The following factors affecting the rubber toughened epoxy resin system were studied: 1. kindsof curing agent used, 2. the M_c value of the matrix, 3. the bonding foce between the dispersed phaseand the matrix. Our experimental result indicates that the average chain length between crosslinks(M_c) is a much more important affecting factor. Chemical bonding between the dispersed phaseand the matrix is also important. A toughening mechanism of rubber toughened epoxy has beenproposed. In the material with relatively low crosslinking density, extensive fracture process stripis formed which is induced by the combined stress field near the rubber particles. The chemical bond-ing between the dispersed phase and the matrix may inerease the strength of the local stress field aboutthe rubber particles which is in favor of broading the fracture process area.     

Role of epoxidized natural Eucommia ulmoides gum in modifying the interface of styrene‐butadiene rubber/silica composites

Eucommia ulmoides gum (EUG) is a renewable and sustainable polymer, which could be used as rubber or plastic by altering its crosslinking density while the complicated extracting process and nonpolar molecular chains limited its application. In this effort, a novel extraction method was introduced, which could simplify the extraction process of EUG. Then, the extracted EUG‐chloroform (CHCl₃) solution was directly used to prepare epoxidized EUG (EEUG) with an epoxy degree of 40.0% to improve its polarity. The epoxidized natural EUG exhibiting both polar and nonpolar motives had an advantage in working as an interfacial compatibilizer for polymer composites, especially bio‐based composites due to its inherent biocompatibility. Accordingly, the role of EEUG in modifying the interface of styrene‐butadiene rubber (SBR)/silica composites were explored. The results showed that EEUG in SBR/silica composites acted not only as a compatibilizer but also as a constructure generating better mechanical properties than other compatibilizers, such as silane couplings, Si‐69 and KH‐550, and epoxidized natural rubber (ENR). The simplified extracting process and the epoxy modification of EUG would extend its application in rubber materials, medical materials, and biopolymer materials.     

Preparation and Characterization of the Hybrids Containing Silica Nanoparticles by Sol-Gel Crosslinking Process

The organic/inorganic hybrid nanomaterials containing silica nanoparticles are synthesized by sol-gel crosslinking process. The tetraethoxysilane (TEOS) and γ-aminopropyltriethoxylsilane as coupling agents are used as a precursor. The 2,4,6-tri [(2-epihydrin-3-bimethyl-ammonium)propyl]-1,3,5-triazine chloride (Tri-EBAC) as crosslinking agent is used to form covalent bonds among the inorganic nanoparticles. The chemical and morphological structures of the organic/inorganic hybrid are characterized with FTIR spectra, ²⁹Si-NMR, x-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and atomic force microscope (AFM). The results show that the organic/inorganic hybrid forms covalent bond between the inorganic nanoparticle and Tri-EBAC. The network organic/inorganic hybrid can form good film with even nanometer particles. The network organic/inorganic hybrids nanomaterial not only exhibits the thermal properties of inorganic compounds, but also exhibits the thermal properties of organic polymer.     

Understanding the effect of filler shape induced immobilized rubber on the interfacial and mechanical strength of rubber composites

Styrene butadiene rubber (SBR) composites with silica, halloysite nanotubes (HNTs) and montmorillonite (MMT) were prepared and the interfacial and mechanical properties were compared to understand the reinforcing behaviours of these fillers based on the results of SEM, DSC, DMA, etc. Due to the formation of interparticle domain, HNTs immobilized more rubber approaching their surface than silica and MMT. Interestingly, only tightly immobilized rubber chains made contribution to the enhancement of interfacial and mechanical strength of SBR composites. This was because the tightly immobilized rubber acted as a bridge in the filler-rubber interface and induced the formation of stretched rubber chains linked filler network when the composites were loaded in tension, while loosely immobilized rubber were easy to slip off from filler surface, causing the separation between filler and bulk rubber. Therefore, silica with more tightly immobilized rubber approaching its surface showed better reinforcing effect on rubber than HNTs and MMT.