Study on Crosslinking Kinetics of PVBC! by Real-time FTIR

利用傅里叶变换红外光谱仪(FTIR)在线追踪聚乙烯基苄基氯(PVBCl)与N,N,N′,N′-四甲基-1,6-己二胺(TMHDA)的交联反应历程,考察了反应时间与温度对交联程度的影响.实验结果表明,随着反应时间的延长,交联程度先迅速增大,而后趋于平缓直至不变;反应温度越高,交联程度越大.对反应进行动力学的研究计算结果显示,该交联反应的反应级数n=4,表观活化能Ea=97.2kJ/mol.     

TMEDA存在下的异戊二烯阴离子均聚合动力学研究

研究了以TMEDA（四甲基乙二胺）为调节剂体系的异戊二烯阴离子均聚合动力学。获得了不同TMEDA／Li及聚合温度对动力学的影响情况。从理论上对聚合机理进行了推导和验证,并通过阿累尼乌斯方程求得了不同反应条件下的聚合活化能。     

聚乙烯基农用塑料薄膜氧化降解特性的红外光谱研究

农用塑料地膜在现代农业中具有举足轻重的地位，但废旧地膜残留及由此引发的微塑料问题日益严重。该文利用傅里叶变换红外光谱仪（Fourier Transform Infrared, FTIR）对土壤中聚乙烯基新地膜和残留地膜表面官能团进行分析和鉴定。结果表明新膜中聚乙烯分子的主要振动形式为-CH2-的弯曲振动及伸缩振动，残膜中除-（CH2）n-外，还具有-C=C-、-C=O-的伸缩振动。FTIR能够准确表征新旧地膜表面官能团的增加、减少及其相对含量，文中基于红外光谱特征峰吸光度引入羰基指数、乙烯键指数及内双键指数对残留地膜氧化降解程度进行半定量分析，此方法操作简便，取样量少，准确表征了聚乙烯基高聚物的氧化降解特性。     

红外光谱法实时跟踪支化聚乙烯亚胺/甲基丙烯酸缩水甘油酯的官能团反应EI北大核心CSCD

支化聚乙烯亚胺（PEI）与甲基丙烯酸缩水甘油酯（GMA）反应体系中,PEI的伯胺基可与GMA上的环氧基和双键发生竞争反应,两者的反应速率显著不同。以红外光谱中的GMA羰基吸收峰为基准,分别对GMA中的环氧基和双键的相对含量随反应时间的变化进行半定量研究,确定PEI中伯胺基与GMA中环氧基的反应活性远大于与双键的反应,在5 ℃～40 ℃温度区间内,温度升高会加速两组官能团之间的反应但更有利于环氧基与胺基的反应。这些结果证明,可以利用红外光谱这一简便的方法来半定量地跟踪反应过程并获得最优化的反应条件。     

有无N_3的无色与近无色天然钻石的荧光与光谱特征研究

通过傅里叶变换红外(Fourier transform infrared,FTIR)光谱结合紫外-可见吸收光谱(UV-Vis absorption spectra)及钻石观测仪(Diamond View)对有无415 nm吸收的无色与近无色天然钻石进行较系统的荧光与光谱特征研究。结果表明:UV-Vis吸收光谱中具有明显415 nm特征吸收的样品所对应的FTIR吸收光谱中1 376~1 359 cm-1处都存在较强且尖锐的吸收峰。相反,UV-Vis吸收谱图中无明显415 nm吸收的样品相应的红外谱图的1 376~1 359 cm-1处无明显的吸收峰位。且部分无415 nm吸收峰的样品在Diamond View下其荧光的颜色可呈现为黄绿色、黄绿色中夹杂蓝色或呈单一的蓝色,因此钻石在Diamond View下荧光呈蓝色是否直接归因于其中的N3尚待进一步商榷。该结论可为合成钻石与天然钻石的鉴定筛选提供一定的技术支持。     

含环氧基丙烯酸酯共聚物体系的交联反应动力学研究

采用程序升温ＤＳＣ法研究了含环氧基丙烯酸酯共聚物／癸二酸体系的交联反应动力学,结合Ｏｚａｗａ方程推导出该交联体系的交联动力学方程,并计算了交联反应的活化能。结果表明,程序升温ＤＳＣ法可较好地克服恒温ＤＳＣ法谱图中因晶态交联剂的熔融峰与交联反应放热峰相互重叠而引起的交联程度难以精确计算的问题,同时也解决了因常规交联反应动力学方程较复杂所带来的诸多问题。本方法为研究含晶态组分固化体系的交联进程提供了一种准确的方法。     

显微红外光谱法热分析mLLDPE/EVA共混体系的结晶过程

采用显微傅立叶转换红外光谱技术研究了mLLDPE／EVA共混物的非等温结晶过程。通过采集150℃～67℃连续降温过程的显微红外光谱数据．运用在等压条件下的van’t Hoff关系式推导计算特征基团在降温结晶过程中起点和终点振动的两种能态吸光度比值的变化和振动能态转变的表现焓变。对比DSC分析结果来看,结晶过程中观察到的两个放热峰分别对应着mLLDPE和EVA的富集区。而从计算得到的各种特征基团在两个放热峰处表现焓变的数据可知．共混物中亚甲基的弯曲振动的表现焓变数值最大,表明在结晶过程中,亚甲基的弯曲振动方式对mLLDPE和EVA分子链段向各自富集区迁移和规整排列贡献最大。     

EVOH/蒙脱土插层型纳米复合材料的研究

将蒙脱土有机化处理,然后将有机化蒙脱土与乙烯-乙烯醇嵌段共聚物(EVOH)通过Brabender流变仪熔融共混,制得纳米复合材料.通过电子透射显微镜、傅里叶变换红外光谱分析,X射线衍射分析等手段对该复合材料进行了结构测试.结果表明:EVOH可以插入有机化蒙脱土片层间;聚乙烯吡咯烷酮改性蒙脱土被EVOH插开的片层距离比季铵盐改性蒙脱土被EVOH插开的片层距离大;有机化蒙脱土在复合材料中比例越小,复合体系中蒙脱土被插开的片层间距越大;当有机化蒙脱土含量为8%时,形成剥离型纳米复合材料;当有机化蒙脱土含量为15%时,形成插层型纳米复合材料.     

X-ray photoelectron spectroscopy (XPS) and FTIR studies of vanadium barium phosphate glasses

Barium vanadophosphate glasses, having composition 50BaO–xV₂O₅–(50 − x)P₂O₅, (x = 0–50 mol%), were prepared by conventional melt quench method. Density, molar volume and glass transition temperature (T_g) were measured as a function of V₂O₅ content. Structural investigation was done using XPS and FTIR spectroscopy. First, substitution of the P₂O₅ by the V₂O₅ in the metaphosphate 50BaO–50P₂O₅ glass increases the density and T_g and decreases the molar volume. When the amount of V₂O₅ increases, all these properties show a reverse trend. XPS measurement found in the O1s, P2p, and V2p core level spectra indicate the presence of primarily P–O–P, P–O–V and V–O–V structural bonds, the asymmetry in the P 2p spectra indeed arises from the spin-orbit splitting of P 2p core level, and more than one valence state of V ions being present. IR spectroscopy reveals the depolymerization of the phosphate glass network by systematic conversion of metaphosphate chains into pyrophosphate groups and then orthophosphate groups. Even though metaphosphate to pyrophosphate conversion is taking place due to breaking of P–O–P linkages, formation of P–O–V and P–O–Ba linkages provide cross linking between short P-structural units, which make the glass network more rigid. Above 10–20 mol% V₂O₅ content, network is highly depolymerized due to the formation of orthophosphate units and V–O–V bridge bonds, resulting in poor cross-linking, making the glass network less rigid.     

Investigation of kinetics and morphology development for polyurethane-urea extended by DMTDA

The relationship between the reactions kinetics and morphology development during the polyurethaneurea (PUU) curing process has been investigated simultaneously by in situ Fourier transform infrared spectroscopy (FTIR). The data of the FTIR spectra showed that with the increase of conversion, the absorbance of NH bands increases and its band sites shifts to lower wavenumbers; the absorbance of free urethane carbonyl kept nearly constant at low conversion, and then decreased much because of the interaction of the formed urea links, and then changed little at high conversion owing to the diffuse control. The band sites of hydrogen bonded urea carbonyl similarly shifted to lower wavenumbers and the absorbance of the hydrogen bonded urea carbonyl, associated with the phase separation of hard segments, became stronger with buildup of hydrogen bond between urea links. The carbonyl bands available during curing process were further assigned. Both interactions, such as hydrogenised effect and phase separation, played a major role in the matrix formation of the PUU polymer.     

聚苯硫醚非等温热分解动力学研究

采用非等温法测定和对比了国产及进口聚苯硫醚(PPS)树脂的热失重动力学行为。运用动力学分析软件计算出动力学参数(活化能Ea、指前因子Z和反应级数n),运用动力学方程估算出两种PPS切片的热分解转化率α、温度T以及时间t之间的关系。结果表明,国产PPS切片的热稳定性略优于进口PPS切片。在低于350℃时,两种切片均十分稳定,因此,在通常的纺丝条件下(300℃左右)发生热分解的可能性均很小。如果在更高的温度范围内加工PPS树脂或使用PPS的产品,热分解的影响则不容忽视。     

FTIR Imaging of Polymer Dissolution

Fast FTIR imaging is applied to the study of binary solvents of glassy polymers. The technique enables the measurement of spatial–temporal infrared data for the dissolution process. It is possible to calculate a dissolution rate as a function of parameters, such as quality of solvent, temperature, as well as changes in the polymer structure, such as molecular weight.     

Plasma-polymerized alkaline anion-exchange membrane: Synthesis and structure characterization

After-glow discharge plasma polymerization was developed for alkaline anion-exchange membranes synthesis using vinylbenzyl chloride as monomer. X-ray photoelectron spectroscopy and attenuated total reflection Fourier transform infrared spectroscopy were used to characterize the chemical structure properties of plasma-polymerized membranes. Ion-exchange capacities of quaternized poly(vinylbenzyl chloride) (QPVBC) membranes were measured to evaluate their capability of hydroxyl ion transport. A mechanism of plasma polymerization using VBC as monomer that accounts for the competitive effects of free radicals polymerization and plasma ablation in the plasma polymerization process was proposed. Our results indicate that plasma discharge power influences the contents of functional groups and the structure of the plasma polymer membranes, which attribute to the coactions of polymerization and ablation. The properties of uniform morphology, good adhesion to the substrate, high thermal stability and satisfying anion conduction level suggest the potential application of QPVBC membrane deposited at discharge power of 20 W in alkaline direct methanol fuel cells.     

交联对聚乙烯醇/明胶生物复合材料溶胀性能的影响

采用溶液共混法制备了聚乙烯醇/明胶（PVA/gelatin）生物复合膜,研究了三种不同的物理和化学交联法（戊二醛（GTA）蒸汽、紫外（UV）照射和干燥脱水交联）对其溶胀性能的影响。结果表明,三种交联方式都能有效地降低其平衡溶胀度,改善其耐水性。戊二醛蒸汽交联对复合材料溶胀性能的影响最大,其中明胶组分的交联是影响PVA/...     

增容剂对PVC/PA6共混物性能的影响

分别以乙烯醋酸乙烯酯接枝马来酸酐(EVA-g-MAH)、丙烯晴-丁二烯-苯乙烯三元共聚物接枝马来酸酐(ABS-g-MAH)及聚乙烯接枝马来酸酐(PE-g-MAH)三种聚合物为增容剂制备了聚氯乙烯/聚酰胺6(PVC/PA6)共混物,采用扫描电子显微镜(SEM)、动态力学分析(DMA)及力学性能测试研究了相容剂对PVC/PA6(80/20)的相形态结构及力学性能的影响。结果表明,三种相容剂对PVC/PA6都具有明显的增容作用,但5%EVA-g-MAH增容PVC/PA6(80/20)的分散相尺寸最小最均匀;三种增容剂增容的PVC/PA6共混物都只有一个玻璃化转变温度(Tg),但EVA-g-MAH增容共混物的Tg略向高温偏移;力学性能测试结果显示,5%的EVA-g-MAH增容的PVC/PA6共混物的缺口冲击强度和拉伸强度分别提高了18%和200%,达到了3.8kJ/m2和46MPa。     

Investigation of irradiated graphene oxide/ultra-high-molecular-weight polyethylene nanocomposites by ESR and FTIR spectroscopy

Graphene oxide/ultra-high-molecular-weight polyethylene (GO/UHMWPE) nanocomposite has a potential application for artificial joints. However, free radicals and antioxidative properties of irradiated GO/UHMWPE were not clearly clarified. In this paper, GO/UHMWPE nanocomposites were prepared and irradiated by gamma-irradiation with a dose of 100 kGy. Afterward, test samples were aged in air. Free radicals and molecular structures of test samples were investigated by electron spin resonance (ESR) spectroscopy and Fourier transform infrared (FTIR) spectroscopy, respectively. These studies indicated that irradiation enhanced GO radical concentrations. And GO radicals were stable in air and even could not be quenched after accelerated aging. GO radicals were superimposed on free radicals of irradiated UHMWPE. Although GO showed free radical-scavenging capacity, the influence of GO on free radicals of irradiated UHMWPE was too weak to be observed in ESR spectroscopy. Free radicals concentrations of irradiated GO/UHMWPE nanocomposites were gradually decayed with aging time evolving in air. Observing the oxidation index values of test samples, it was proposed that irradiated GO/UHMWPE might show very weak antioxidative properties.     

热重法研究含氟聚酰胺酸的亚胺化反应动力学

采用动态热重法(TG)对4,4’-二氨基二苯氧基丙烷(BAPP)和4,4’-六氟亚异丙基-邻苯二甲酸酐(6FDA)缩聚生成的含氟聚酰胺酸动力学进行研究。采用积分法结合31种动力学函数来判断亚胺化反应的函数g(α),由Ozawa、KAS和迭代法求取活化能Ea值。从而得到了亚胺化反应的动力学参数,即反应的动力学函数为g(α)=(1-α)-1-1,平均活化能Ea=81.93 kJ/mol,指前因子A的平均值为1.91×109s-1。