γ射线辐照聚偏氟乙烯接枝苯乙烯磺酸乙酯

以聚偏氟乙烯(Polyvinylidene fluoride,PVDF)树脂为基材,采用γ射线预辐射接枝法在PVDF树脂上接枝苯乙烯磺酸乙酯(Ethyl styrenesulfonate,ETSS),探讨吸收剂量、接枝温度、接枝反应时间及单体浓度对接枝率的影响。之后在95℃水解PVDF-g-PETSS聚合物得到PVDF接枝苯乙烯磺酸(PVDF-g-PSSA)离子交换树脂。红外光谱、X射线光电子能谱、热重分析证明PVDF-g-PETSS及PVDF-g-PSSA被成功制备。当接枝率为120%时,PVDF-g-PSSA的离子交换容量达到2.05 mmol/g。这种将带有磺酸基团的单体通过辐照接枝引入PVDF基材然后水解的方法简单、高效、污染小,有望在离子交换树脂及离子交换膜的制备中得到应用。     

预辐照聚偏氟乙烯粉体接枝甲基丙烯酸缩水甘油酯

用<'60>Co γ射线预辐照接枝法,在聚偏氟乙烯(PVDF)粉体上接枝甲基丙烯酸缩水甘油酯(GMA),制备了含有高活环氧基团的PVDF-g-PGMA粉体.结果表明,接枝率随反应时间增大,5 h后基本不变;接枝率随辐照剂量增大;单体浓度较低时接枝率随单体浓度增大,单体浓度>15%后接枝率减小;温度较低时并无接枝反应发生,温度高于30℃,接枝率随着温度增加,50℃时达最大值,温度继续升高接枝率又有所降低.傅里叶红外光谱测试表明接枝物为PVDF-g-PGMA共聚物;差热扫描量热仪分析表明,接枝粉体的熔融温度Tm以及熔融焓△Hf均随接枝率的增大而降低.对接枝粉体进行化学改性得到了多胺基吸附材料.实验证明,改性粉体材料对Cu2+有较好的吸附作用.     

SBS粉体预辐射接枝丙烯酸研究

以60Coγ射线为辐射源,对SBS粉体在空气中进行预辐照,然后将一定量粉体置于丙烯酸水溶液体系中进行接枝反应。研究了反应时间、反应温度、单体浓度和吸收剂量对接枝率的影响。傅里叶变换红外光谱(FTIR)分析结果证明了羧酸基团的成功引入,并对接枝后粉体的热重分析,结晶度和表面形貌进行了研究。     

PVDF粉体预辐照接枝甲基丙烯酸缩水甘油酯制备锂离子二次电池隔膜研究

以聚偏氟乙烯（PVDF）粉体为基材,采用预辐照接枝方法,在PVDF粉体上用乳液聚合接枝甲基丙烯酸缩水甘油酯（GMA）,并采用溶液铸膜的方法制备了PVDF-g-PGMA膜。利用红外光谱（FTIR）,扫描电子显微镜（SEM）,压汞仪,电导率测试等分析表征手段对制备的PVDF—g-PGMA膜进行了表征。在氩气手套箱中组装成扣式电池,在电池测试系统上测试扣式电池的充放电循环性能。测试结果表明,在相同制备条件下,以PVDF-g-PGMA作为隔膜的锂离子电池性能优于以PVDF作为隔膜的锂离子电池性能。     

预辐射接枝丙烯酰胺改性PVDF粉体及其亲水性滤膜的制备

通过γ射线预辐射接枝方法将丙烯酰胺(Acryl amide,AAm)单体接枝到聚偏氟乙烯Poly(vinylidene fluoride),PVDF]粉体上,通过测定粉体接枝前后氟元素含量的变化来计算接枝率.研究了同一单体浓度下,接枝率随反应时间的变化规律,并将具有不同接枝率的改性粉体溶解在N-甲基吡咯烷酮(N-met...     

SBS辐射接枝共聚研究(Ⅱ):线型SBS液固相辐射接枝MAA

利用γ射线辐射接枝法制备苯乙烯-丁二烯-苯乙烯(Styrene—Butadiene—Styrene,SBS)粉体接枝甲基丙烯酸(MAA)聚合物,讨论了单体浓度、辐照剂量、气氛及辐照状态等因素对接枝率的影响,并采用傅立叶红外光谱(FT-IR)、差示扫描量热分析(DSC)、凝胶渗透色谱(GPC)、扫描电镜(SEM)、动态剪切流变(DSR)等分析手段对接枝聚合物进行了表征。研究结果表明,平均粒径为0．2mm的线型SBS粉体在辐照剂量为12kGy、剂量率为0．75kGy／h、MAA／SBS的质量比为0．6时,可获得最大接枝率。FTIR谱出现1705cm^-1。处羰基的吸收峰证实了接枝聚合物的存在,分子量分布测定表明SBS-g-MAA聚合物的分子量分布变宽,动态剪切流变中接枝聚合物的粘度增大,表明单体在SBS链上有接枝链的增长;热分析曲线中聚苯乙烯嵌段的玻璃化转变温度升高,损耗因子转折温度升高,都说明单体MAA对PS嵌段的影响较大。     

SBS辐射接枝共聚研究(II):线型SBS液固相辐射接枝MAA

利用γ射线辐射接枝法制备苯乙烯-丁二烯-苯乙烯(Styrene-Butadiene-Styrene,SBS)粉体接枝甲基丙烯酸(MAA)聚合物,讨论了单体浓度、辐照剂量、气氛及辐照状态等因素对接枝率的影响,并采用傅立叶红外光谱(FT-IR)、差示扫描量热分析(DSC)、凝胶渗透色谱(GPC)、扫描电镜(SEM)、动态剪切流变(DSR)等分析手段对接枝聚合物进行了表征。研究结果表明,平均粒径为0.2mm的线型SBS粉体在辐照剂量为12kGy、剂量率为0.75kGy/h、MAA/SBS的质量比为0.6时,可获得最大接枝率。FTIR谱出现1705cm-1处羰基的吸收峰证实了接枝聚合物的存在,分子量分布测定表明SBS?g?MAA聚合物的分子量分布变宽,动态剪切流变中接枝聚合物的粘度增大,表明单体在SBS链上有接枝链的增长;热分析曲线中聚苯乙烯嵌段的玻璃化转变温度升高,损耗因子转折温度升高,都说明单体MAA对PS嵌段的影响较大。     

辐射接枝制备有机-无机纳米杂化粒子及其分散性能

本文采用共辐射接枝技术,在室温真空氛围中利用γ射线引发一步制备聚偏氟乙烯(PVDF)接枝改性的钛酸钡(BT)有机-无机纳米杂化粒子.通过傅里叶变换红外光谱(FTIR)、热失重分析仪(TGA)以及透射电子显微镜(TEM)对产物进行分析,证明了PVDF成功接枝在钛酸钡纳米粒子表面.利用差示扫描量热仪(DSC)与X射线衍射仪...     

SBS液相共辐射接枝马来酸酐/苯乙烯二元单体研究

本文在苯乙烯-丁二烯-苯乙烯嵌段共聚物（Styrene—Butadiene—Styrene triblock copolymer,SBS）辐射接枝马来酸酐（Maleicanhydride,MAH）的基础上,进行MAH／苯乙烯（Styrene,St）二元单体辐射接枝研究,讨论了MAH／St比例和总浓度及吸收剂量对接枝率的影响。就MAH接枝产物SBS-g-MAH和MAH／St二元接枝产物SBS-g-MAH／St进行了傅立叶红外光谱（Fouriertransforminfraredspectroscopy,FFIR）、热重（Thernlalgravimetric,TG）分析与差示扫描量热（Differentialscanningcalorimetry,DSC）分析等表征与分析。结果表明：MAH／St二元接枝可明显提高MAIl接枝率。     

SBS辐射接枝共聚研究(Ⅰ):SBS/MMA液相辐射接枝

利用^60Coγ射线对苯乙烯-丁二烯-苯乙烯(Styrene-Butadiene-Styrene,SBS)嵌段共聚物进行辐射接枝改性。研究了SBS／甲基丙烯酸甲酯(Methyl methacrylate,MMA)溶液体系的辐射接枝共聚反应,探讨了辐照剂量、单体浓度、SBS型号对接枝率的影响。并用红外光谱(FT-IR)对接枝共聚物进行了表征,用差示扫描量热仪(DSC)测量了接枝共聚物SBS-g-MMA的热性能。     

Graft co-polymerization of maleic acid and vinyl acetate onto poly（vinylidene fluoride） powder by pre-irradiation technique

Binary monomers of maleic acid and vinyl acetate are grafted onto poly(vinylidene fluoride) (PVDF) powder by pre-irradiation induced graft polymerization technique in emulsion solution. The co-grafting of binary monomers is successfully proved by FT-IR spectroscopy analysis. The influences of the absorbed dose, reaction temperature, reaction time, total concentration of monomers, and feed ratio of binary monomers on the degree of grafting are investigated. The thermal property of grafted PVDF powder was characterized by differential scanning calorimetry (DSC) and thermo-gravimetry analysis (TGA).     

Determining the degree of grafting for poly（vinylidene fluoride） graft-copolymers using fluorine elemental analysis

Acrylic acid (AAc) and styrene (St) were grafted onto poly(vinylidene fluoride) (PVDF) powder or membrane samples by pre-irradiation graft copolymerization.The grafted chains were proved by FT-IR spectroscopy analysis.The degree of grafting (DG) of the grafted PVDF was determined by fluorine elemental analysis (FEA) method,and was compared with the DGs determined by weighing method,acid-base back titration method and quantitative FT-IR method.The results show that the FEA method is accurate,convenient and universal,especially for the grafted polymer powders.     

Preparation and characterization of proton exchange membranes from polystyrene grafted poly（vinylidene fluoride） powder

Proton exchange membranes(PEMs) were prepared in three steps:graRing of polystyrene onto PVDF powder using pre-irradiation graft polymerization technique, processing the grafted PVDF powder into membranes of around 50-μm thickness, and sulfonating them with cholorosulfonic acid to form poly(vinylidene fluoride)-g-poly(styrene sulfonic acid) membranes. Kinetics of the graft polymerization was studied. The existing of polystyrene side-chains in the grafted PVDF powders, and PSSA groups in PEMs, were proved by FT-IR. Properties of the PEMs, i.e. the ion exchange capacity, water uptake, proton conductivity, thermal property and oxidative stability,were characterized. Dependence of properties on the degree of grafting was investigated, too.     

Grafting of PNIPAAm on PVDF submicroscopic tracks induced by the active sites remainders of the etching process

The present work is part of a systematic study that involves different polymeric substrates and monomers with the purpose to induce grafting on etched tracks. The residual active sites produced by heavy ion beams, remaining after the etching process, were used to start the grafting process. In order to produce tracks on foils of poly(vinylidene fluoride) (PVDF) they were irradiated with ²⁰⁸Pb of 25.62 MeV/n or with 115 MeV Cl ions. Then, they were etched and grafted with N-isopropylacrylamide (NIPAAm) monomers. Experimental curves of grafting yield as a function of fluence with the etching time as a parameter were measured. Also, the grafting yield as a function of the grafting and etching time was obtained. The replica method allowed the observation of the shape of the grafted tracks using transmission electron microscopy (TEM). In addition NIPAAm grafted foils were analyzed using Fourier transform infrared spectroscopy (FTIR).     

Radiation synthesis and characteristics of PTFE-g-PSSA ion exchange membrane applied in vanadium redox battery

Radiation-induced grafting of styrene onto polytetrafluoroethylene （PTFE） membranes was studied by a simultaneous irradiation technique. Grafting was carded out using γ-radiation from a ^60Co source at room temperature. Effects of absorbed dose, atmosphere, dose rate, and the concentration of initial monomer on the degree of grafting （DOG） were investigated and the most appropriate grafting condition was obtained. Subsequently, sulphonation of the grafted PTFE membrane （PTFE-g-PS） was carded out and a series of ion exchange membranes （PTFE-g-PSSA） was prepared. Further characterizations of FTIR, TGA, and SEM testified that grafting and sulphonation of the membranes were successfully processed; moreover, grafting of styrene not only occurred in the surface of PTFE membrane, but also in the micropores of the membrane. Ion exchange capacity （IEC） and conductivity were found increase with the grafting yield. The results suggest that at a low dose, such as 17 kGy, the ion exchange membrane （IEM） which will be suitable for vanadium redox battery （VRB） use can be obtained.     

HDPE预辐射接枝NIPA/AAc的性能研究

高密度聚乙烯膜(HDPE)在N2保护下预辐射接枝N-异丙基丙烯酰胺(NIPA)和丙烯酸(AAc),制备了既具有温度敏感又兼具pH敏感的水凝胶,应用傅立叶变换红外光谱(FTIR)、差示扫描量热仪(DSC)、扫描电镜(SEM),研究了该水凝胶的接枝物组成、物理性质以及表面形态。结果表明接枝复合物在不同pH值的介质环境中表现出不同的温敏特性：在酸性条件下随温度升高,体积溶胀增加,表现为“热胀温敏水凝胶”;在中性或碱性条件下随温度升高,溶胀体积在相变温度附近急剧收缩,表现为“热缩温敏水凝胶”。     

Plasma Induced Grafting of PMMA onto Titanium Dioxide Powder

Grafting of polymer of methyl methacrylate （PMMA） onto titanium dioxide powder is investigated in this paper. The graft polymerization reaction is induced by dielectric-barrier- discharge produced N2 plasma treatment of titanium dioxide surfaces. IR, XPS and TGA results show that PMMA is grafted onto the surfaces of titanium dioxide powder. And crystal structure of the titanium dioxide powder observed with XRD spectra is unchanged after plasma graft polymerization.