芘基化超支化聚乙烯共聚物的合成及其在石墨烯制备与功能化中的应用

发布时间：2018-02-24 15:22

本文关键词： 超支化聚乙烯共聚物芘基化石墨烯 CH-π作用 π-π作用　出处：《浙江工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：作为单原子厚的两维碳纳米材料,石墨烯显示出优异的导电、导热、力学等性能,在电子器件、生物医用材料、传感元件、能源材料及高性能聚合物复合材料等领域具有重要的应用前景。研究如何通过简单的工艺,高效制备获得低缺陷石墨烯,并对其表面进行功能化修饰以促进其应用和研究的实施,对于该领域的发展具有重要意义。本论文利用烯烃配位聚合后过渡金属催化剂α-二亚胺钯(Pd-diimine)独特的链行走聚合机理,将多重芘基和异丁酰溴(可引发ATRP聚合)引入超支化聚乙烯(HBPE)支链末端,获得芘基化HBPE二元和三元共聚物,对所得共聚物的结构进行了深入的表征,揭示了共聚反应规律及共聚物组成调控方法;在此基础上,考察了所得共聚物在低沸点有机溶剂中高效制备石墨烯的能力,同时对体系内聚合物与石墨烯间的非共价作用规律进行了研究。具体总结如下:(1)在乙烯压力为0.1 MPa、聚合温度为25~35℃下,利用Pd-diimine催化剂催化乙烯和芘单体共聚不同的时间,基于链行走二元乙烯共聚机理,以一步法工艺合成获得了一系列芘基化HBPE二元共聚物;分别利用氢核磁共振波谱(1HNMR)、凝胶渗透色谱(GPC)、傅里叶变换红外光谱(FTIR)、差示扫描量热分析(DSC)、激光动态光散射(DLS)、紫外-可见吸收光谱(UV-Vis)和熔融流变测试等手段对所得共聚物的结构进行了表征,考察了上述聚合反应的活性/可控特征,以及聚合温度、时间及投料浓度对聚合产物分子量、链形态及组成的影响规律。通过研究发现:借助pd-diimine催化的链行走乙烯共聚反应,可成功地将多重芘基引入hbpe结构中,获得芘基化hbpe二元共聚物;通过聚合温度和芘单体投料浓度的改变,可对共聚物中芘基比例进行有效调控;同时,通过聚合时间的改变可对共聚物的分子量进行调节。在乙烯压力0.1mpa、35℃、芘单体投料浓度0.5m下,由pd-diimine催化乙烯共聚24h,可获得窄分布(pdi=1.16)的芘基化hbpe共聚物,所含的芘基比例可高达7.63mol%。(2)在上述研究基础上,在乙烯压力0.1mpa和聚合温度25~35℃下,进一步利用pd-diimine催化剂催化乙烯、芘单体和biea(同时含有丙烯酰基和异丁酰溴基团)共聚,基于链行走三元乙烯共聚机理以一步法工艺合成获得了一系列hbpe三元共聚物;并利用上述各类表征手段对所得三元共聚物的结构与组成进行了表征,考察了聚合温度和单体投料浓度对共聚物组成的影响规律。研究发现:利用上述链行走三元乙烯共聚机理,可同时将多重芘基和异丁酰溴功能基团引入hbpe支链末端,获得芘基化hbpe三元共聚物;同时,通过聚合温度和功能单体投料浓度的改变,可对所得共聚物中芘基和功能基团的比例进行有效调节。在乙烯压力0.1mpa、35℃下,利用pd-diimine催化剂催化芘单体和biea共聚(投料浓度:芘单体0.3m、biea0.6m),经聚合24h,可成功获得窄分布hbpe三元共聚物(pdi:1.23),结构中芘基和异丁酰溴基团分别达0.6mol%和4.0mol%。(3)在超声作用下,利用所得芘基化hbpe二元共聚物在低沸点有机溶剂中(thf、氯仿)剥开天然石墨,制备获得了一系列稳定的石墨烯有机溶液;通过uv-vis吸收光谱技术对石墨烯浓度进行了测定,同时分别利用高分辨透射电子显微镜(hrtem)、原子力显微镜(afm)、广角x射线衍射(waxrd)、拉曼光谱(raman)和x射线光电子能谱(xps)等技术对所得石墨烯的结构及表面缺陷进行了深入表征。考察了超声时间、投料比例、芘基引入等因素对体系内石墨烯制备效率的影响规律。通过研究发现:在thf或氯仿中,利用所得芘基化hbpe二元共聚物借助超声可高效剥开天然石墨,获得稳定的石墨烯有机溶液,通过投料比例的改变,可对石墨烯浓度进行有效调节。同时,较之单一的hbpe,芘基的引入可进一步提高石墨烯制备效率。所得石墨烯厚度约为3~5层,具有分散稳定、结构缺陷少的优点。(4)以上述制备获得的石墨烯有机溶液为基础,进一步通过真空抽滤制备获得了一系列石墨烯/芘基化hbpe共聚物复合材料,并分别通过uv-vis、ftir和tga对其进行了表征。结果表明,较之于单一的hbpe,所得芘基化hbpe与石墨烯表面存在更稳固的非共价作用,该作用可归结于ch-π和π-π协同作用。借助该协同作用,部分共聚物可稳固地非共价吸附于石墨烯表面(在thf中,38.95%;在氯仿中,32.59%)总之,本文通过研究,已为芘基化hbpe共聚物的合成,以及利用所得共聚物实现低缺陷石墨烯高效制备及表面功能化建立了新的方法和思路,所得石墨烯在高性能聚合物/石墨烯纳米复合材料领域具有重要而广阔的应用前景。
[Abstract]:As the two dimensional single atom thick carbon nano materials, graphene exhibits excellent conductivity, thermal conductivity, mechanical properties, electronic devices, biomedical materials, sensors, has an important application field of energy materials and high performance polymer composite materials. To study how through a simple process, efficient preparation for low defect on the surface of graphene, and modified in order to promote the implementation of its application and research, has important significance for the development of the field. This paper uses olefin coordination polymerization after transition metal catalyst alpha two palladium imine (Pd-diimine) unique chain walking polymerization mechanism, multiple pyrene and isobutyl bromide (can ATRP polymerization) into hyperbranched polyethylene (HBPE) branched end, obtain pyrene HBPE two yuan and three yuan for the structure of copolymer, copolymer of in-depth characterization, reveals the copolymerization The composition of the copolymer and controlling method; on this basis, effects of the copolymer in organic solvent with low boiling point in the high ability of preparation of graphene, the non covalent interaction law system between polymer and graphene were studied. The concrete are summarized as follows: (1) in ethylene pressure is 0.1 MPa, the polymerization temperature was 25~35 C, the use of Pd-diimine catalyst for ethylene and pyrene monomers in different time, chain walking two yuan ethylene copolymerization mechanism based on one-step synthesis process to obtain a series of pyrene HBPE two yuan copolymer; respectively by hydrogen nuclear magnetic resonance spectroscopy (1HNMR), gel permeation chromatography (GPC), Fourier transform infrared the spectrum (FTIR), differential scanning calorimetry (DSC), dynamic laser light scattering (DLS), UV Vis absorption spectroscopy (UV-Vis) structure means and melt rheological test of the copolymers were characterized and investigated the poly Reaction activity / controlled characteristics, as well as the polymerization temperature, time and feed concentration on the molecular weight of the polymerization products, influence of chain morphology and composition. Through the study found: with the help of Pd-diimine catalyzed copolymerization of vinyl chain walking, can be successfully introduced multiple pyrene HBPE structure, obtained two HBPE pyrene copolymer; through the polymerization temperature and the pyrene monomer feed concentration changes, can effectively control of pyrene in the copolymer ratio; at the same time, the polymerization time changes on molecular weight of the copolymer of ethylene pressure regulation. In 0.1MPa, 35 DEG C, pyrene monomer feed concentration 0.5m, ethylene catalyzed by Pd-diimine co 24h, can obtain the narrow distribution (pdi=1.16) of pyrene HBPE copolymer, pyrene contained in the proportion of up to 7.63mol%. (2) on the basis of the above study, the ethylene pressure 0.1MPa and polymerization temperature of 25~35 DEG C, further use of Pd-diimine. Catalyzed ethylene, pyrene monomer and BIEA (containing acryloyl and isobutyryl bromine group) copolymerization, chain walking three yuan ethylene copolymerization mechanism by one-step synthesis process to obtain a series of HBPE copolymers based on three yuan and three yuan; the structure and composition of the copolymer was characterized by the various characterization means were employed to investigate the influence of temperature and monomer concentration on the copolymer composition. The study found that: the chain walking three yuan at the same time the ethylene copolymerization mechanism, multiple pyrene and isobutyryl bromide introduced functional groups of HBPE branched chains, obtained three yuan of pyrene HBPE copolymer; at the same time, feed concentration through the polymerization temperature and monomer change, of base and functional groups in the copolymer of pyrene were effective in Ethylene Regulation. The pressure 0.1MPa, 35 DEG C, the use of Pd-diimine catalyst catalytic pyrene monomer and BIEA copolymer (vote The concentration of pyrene monomer: 0.3m, biea0.6m, 24h) can be successfully obtained by polymerization, narrow distribution of HBPE copolymer (pdi:1.23), three in the structure of pyrene and isobutyryl bromine group was 0.6mol% and 4.0mol%. respectively (3) under the action of ultrasonic, the pyrene HBPE two copolymer in low boiling point organic the solvent (THF, chloroform) peel natural graphite, obtained a series of stable graphene organic solution; through the UV-Vis absorption spectroscopy of graphene concentration were measured respectively at the same time, the use of high resolution transmission electron microscopy (HRTEM), atomic force microscopy (AFM), wide-angle X-ray diffraction (waxrd), X Raman spectroscopy (Raman) and X ray photoelectron spectroscopy (XPS) techniques such as structure and surface defects of the graphene have been investigated. Effects of ultrasonic time, feed ratio, influence factors on the efficiency of pyrene into preparation system layeredgraphene. Through research Found in THF or chloroform, the pyrene HBPE two copolymer by ultrasonic can effectively peel the natural graphite, graphene obtained stable organic solution, the feeding ratio of the change of graphene concentration adjust effectively. At the same time, compared with the single HBPE, the introduction of pyrene can be further improved the preparation of graphene. The graphene efficiency is about 3~5 thick layer, with advantages of stable dispersion, less structural defects. (4) graphene organic solution on the basis of the preparation by vacuum filtration, further prepared a series of graphene / pyrene HBPE composites, respectively. The UV-vis was characterized by FTIR and TGA. The results showed that compared with the single HBPE, there are non covalent interactions more stable income pyrenyl HBPE and the graphene surface, the effect can be attributed to the ch- PI and Pi Pi through the coordination with the cooperation. Effect of stably non covalent portion of the copolymer adsorbed on the surface of graphene (THF, 38.95%; 32.59% in chloroform, in short), this paper has synthesized HBPE copolymers of pyrene, and the use of the copolymer to achieve low defects in the graphene efficient preparation and functionalization of established methods and ideas the resulting graphene has important application prospects and broad in high performance polymer / graphene nanocomposites.

【学位授予单位】：浙江工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ127.11;TB332

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