用13C-NMR研究气相法乙烯-丁烯共聚物

用核磁共振（＾１３Ｃ－ＮＭＲ）研究了不同丁烯投料量的气相法乙烯－丁烯共聚物,给定了＾１３Ｃ－ＮＭＲ各吸收峰化学位移归属,计算了乙烯－丁烯共聚物的三元序列分布、链节数和链节长度。用沸己烷抽担乙烯－丁烯共聚物,对不溶物、可溶物的＾１３Ｃ－ＮＭＲ谱研究表明,经抽提后不溶物分子链中丁烯链节减少了,惭烯链节增加;可溶物分子链中丁烯链节增加,乙烯链节减少。＾１３Ｃ－ＮＭＲ研究表明,对不同丁烯投料量的乙烯－丁烯     

高分辨固体~（13）C－NMR和XPS技术表征碳的骨架结构

本文用高分辨固体￣（１３）Ｃ－ＮＭＲ和ＸＰＳ技术表征了抚顺老虎台气煤吡啶抽提残煤及其热解加氢产物中四氢呋喃不溶／吡啶可溶物和吡啶不溶物的碳骨架结构。固体￣（１３）Ｃ－ＮＭＲ谱的研究结果表明：三个样品的芳香组体积平均碳原子数分别是１９，２２，２５个，芳香环数目依次是５．０，５．８，６．７个。随样品中碳元素百分含量（Ｃ％）的增加，芳香组体积的平均碳原子数目和芳环数目都增加。ＸＰＳ分析结果表明：碳元素主要以类石墨化芳香核的形式存在，而且这类碳的比例随Ｃ％的增加而增加。上述结果为研究气煤的大分子结构提供了有价值的信息。     

^13C核磁共振在表在活性剂分析中的应用

本文论述了近年来^13C－NMR在测定表面活性剂结构，确定异构体同系物的组成，进行表面体及同系物的组成，进行表面活性剂混合物中各组分的定量分析，以有物化性能的研究等方面的最新成果。     

暗色土不同粒度腐植酸组分的碳—13核磁共振光谱（^13C—NMR）及元素组成

因为腐植酸粒度(分子)变化范围大(Swift 1985),所以,以不同粒度腐植酸组分的差异为基础对其组分的结构信息进行比较,对于重建腐植酸整体构象很重要。凝胶渗透色谱法(GPC)是制得不同粒度连续腐植酸组分最有效的技术。但是,要制得严格的不同粒度组分,技术方面(如分离柱类型和理论塔板数限制)阻碍了制备用于各类腐植酸分析的     

乙烯-乙酸乙烯酯共聚物(EVA)的性能及应用

本文综述了乙酸乙烯酯(VA)含量和熔体流动速率(MFR)对乙烯-乙酸乙烯酯共聚物(EVA)性能的影响以及EVA树脂的应用。     

用固体13C-NMR表征丙烯酸酯类抗冲型改性剂的核壳结构

采用固体^13C-NMR对具有核壳结构的丙烯酸酯类抗冲型改性剂（ACR）中的聚甲基丙烯酸甲酯（PMMA）进行了测试。结果表明，ACR中聚丙烯酸丁酯（PBA）核与PMMA壳具有良好的相容性并形成了中间相，由PMMA旋转坐标系中自旋晶格弛豫时间得出PMMA中间相占总PMMA的摩尔分数为23%。由自旋-自旋作用时间得出PMMA中间相与非中间相摩尔比为3/7。     

四氟乙烯与乙烯共聚物性能简介

ETFE塑料,英文名称:Ethylene-tetrafluoroethylene,又称氟塑料-40。简称:ETFE或F-40。由四氟乙烯与乙烯共聚而成,是一种耐高温的氟塑料,使用温度范围为-60～180°C,四氟乙烯含量在四分之三以上(按重量比),因此它保持聚四氟乙烯高耐候性、高化学稳定性、高介电性的同时,又具有聚乙烯的优良加工性能。它的抗拉强度能达到50 MPa,是聚四氟乙烯树脂的两倍,ETFE加工产品有很好的市场前景,目前国内已有企业开始试制。     

乙烯-乙烯醇共聚物在食品包装领域的应用

“打造传播创新媒体,搭建中外交流平台”是本刊新时期定下的目标,几年来,我们一直朝着这一目标奋斗。经过半年多的筹备,在今年中国国际橡塑展期间,本刊策划的一系列活动如期举办,并取得了积极的效果:发起并承办“中国塑料行业新材料、新技术国际论坛—2006中、日、韩及台湾区塑料新材料、新技术研讨会”和“中、日、韩及台湾区塑料行业恳谈会”;组织了中英两国塑料协会、企业间的联谊活动;与国外媒体探讨合作……为了让读者了解更多资讯,我们制作了本期《特别报道》。     

脲醛树脂胶粘剂~(13)C核磁共振分析

采用常规化学分析和13C核磁共振相结合的方法,分析研究了脲醛树脂胶粘剂性能与结构的关系。结果表明:在摩尔配比F:U=1.2:1时,粘度越高,游离尿素的含量越低,羟甲基的含量越低,游离甲醛含量降低; 树脂产品的粘度低,聚合度也低,羟甲基的含量偏高,粘接性能下降,同时游离甲醛含量上升,而适量苯酚的添加可改善树脂结构,是一种优化树脂的途径。当增大摩尔配比到F:U=1.4:1时,尿素含量下降,游离甲醛含量上升。因此,摩尔配比的选择在很大程度上影响脲醛树脂的性能。     

用CP/MAS~(13)C NMR研究壳聚糖的分子运动

用固体交叉极化/魔角旋转(CP/MAS)13CNMR测定了壳聚糖、热失水壳聚糖和戊二醛交联壳聚糖在固态下不同峰位13C的弛豫时间,对不同样品的不同峰位碳弛豫时间的大小进行了解释,并根据弛豫时间的测定值对这3种不同壳聚糖样品的分子运动状态进行了描述。结果表明,壳聚糖受热失去吸附水以后,所有位置碳的弛豫时间均有所延长,以C2,6的弛豫时间延长幅度最大,分子运动受阻;壳聚糖用戊二醛交联以后,所有13C信号的线宽均大幅度增加,而弛豫时间显著降低,分子运动加剧。     

两种罗汉果多糖的IR及13C NMR分析

利用FT IR和13C NMR技术对罗汉果中的两种多糖SGPS1(Siraitia grosvenorii Polysaccharides,SGPS)和SGPS2进行分析。从SGPS1和SGPS2的红外吸收(4000-500 cm-1)可知,它们具有典型的多糖吸收特征,SGPS1中的单糖残基以吡喃环和呋喃环的形式存在,SGPS2中的单糖残基以α-吡喃环的形式存在。同时运用13C NMR证实了这两种多糖的单糖残基环状构型及糖苷键构型。     

稳定同位素13C在生物医学研究中的应用

稳定同位素13C因其具有安全、无损伤和非侵害性等特点己被广泛应用于生物医学等研究领域。尤其是应用不同的13C标记物所进行的呼气试验,更是在生物学、临床医学的诊断与研究中发挥了重要作用,应用前景广阔。     

Change in the structure of poly(tetramethylene succinate) under tensile stress monitored with solid state C NMR

A new solid-state NMR experimental equipment was developed to monitor the structural change of polymer and protein fibers under active uniaxial deformation. The equipment was applied to monitoring change in the structure of a biodegradable aliphatic polyester fiber, poly(tetramethylene succinate) (PTMS; [-O(CH₂)₄OCO-(CH₂)₂CO-]_n), as a function of tensile stress. The crystal transition from α to β forms for PTMS was induced by stress and monitored by the change of the methylene region in the ¹³C NMR spectra. The ¹³C chemical shielding constant for the model compound of poly(tetramethylene succinate) was calculated using the GIAO-CHF (gauge invariant atomic orbitals-coupled Hartree-Fock) with ab initio 6-311G^∗∗ basis set. This calculation acceptably explains the experimental results.     

An investigation of 1H and 13C longitudinal relaxation and relaxation in the rotating frame in solid poly(N‐vinylcarbazole)

¹H and ¹³C longitudinal relaxation times (T₁) and relaxation times in the rotating frame (T_1ρ) have been measured for poly(N‐vinylcarbazole) in the solid state in air and nitrogen atmospheres in an attempt to elucidate molecular motions. In air, the T₁ relaxation of both ¹H and ¹³C was dominated by interaction with absorbed paramagnetic oxygen. In nitrogen, the ¹³C T₁ relaxation times were long (>300 s) and were averaged by ¹³C–¹³C spin diffusion. The ¹³C T_1ρ relaxation times showed an exponential dependence on the strength of the rotating ¹³C magnetic field and were thus controlled by spin–spin processes rather than spin–lattice processes. © 2001 Society of Chemical Industry     

Identification of Turkish extra virgin olive oils produced in different regions by using NMR (1H and 13C) and IRMS (13C/12C)

Isotope ratio mass spectroscopy (IRMS) and nuclear magnetic resonance (NMR) spectroscopy techniques are two of the analytical methods that are used to characterize food products. The aim of this study is to classify extra virgin olive oil (EVOO) samples collected from different regions of Turkey based on ¹H and ¹³C NMR spectra along with IRMS δ¹³C carbon isotope ratio data by using chemometrics multivariate data analysis methods. A total of 175 EVOO samples were analyzed in 2014/15 and 2015/16 harvest seasons. Multivariate classification and clustering models were used to identify geographical and botanical origins of the EVOOs. IRMS results showed that there was no significant difference in terms of δ¹³C values between the years in terms of harvest year (p > 0.05), only extraction phase and variety were statistically significant factors (p < 0.05). The interactions of the factors showed that the harvest year × variety interaction is important. The outcomes of this research clearly indicated that considering the partial least squares discriminant analysis result with NMR spectra, the percent success of the model in the South Marmara, North Aegean, and South Aegean region samples were 95%, 95.7%, and 96.4% in the model set, respectively. The results showed that by using classification and clustering models, geographic marking and labeling of these oils can be carried out regardless of differences in year and production systems (2 and 3 phase extraction system) according the NMR analysis.     

13C NMR Study PP/ROSIN Blends

Abstract

The solid state NMR technique was employed to investigated the homogeneity level of the melting mixtures of polypropylene (PP) and glycerol ester of hydrogenated rosin (ester gum) prepared at different proportions and under selected conditions. The results were discussed in terms of the blend domains with distinct mobilities at kilohertz range. Up to 30% of rosin the blends revealed a slight increase in the proton spin lattice relaxation time in the rotating frame (T1Hp) values caused by increasing the mobility process of PP domains. The presence of one phase at the time scale of that relaxation parameter suggests sample homogeneity. The T1Hp value for blend with 50% of rosin indicated incompatibility.     

Structural analysis of oriented poly(ε‐caprolactone) including CaCO3 particles with 13C solid‐state NMR

The results of a study of the relation between the oriented structure and drawn Poly(ε‐caprolactone) specimens including CaCO₃ particles and their dynamic mechanical properties are presented. The loss elasticity, E″, showed almost the same curve for both undrawn sheets and drawn sheets as a function of CaCO₃ content. On the other hand, the storage modulus, E′, of drawn sheets increased nonlinearly with increasing CaCO₃ content, and their curve showed lower E′ values than those of undrawn sheets. By simulation of ¹³C CP NMR spectra of drawn PCL/CaCO₃ sheets, both oriented and unoriented components were observed. The distribution parameter, p, of drawn PCL/CaCO₃ sheets was 13°, which was larger than those (8°) of drawn PCL. Further, the fraction of the unoriented component increased with increasing CaCO₃ content. Thus, adding CaCO₃ particles into the PCL, the arrangement of the oriented component was disturbed and decreased. In addition, from the line shape analyses of ¹³C CP MAS NMR spectra, four peaks were obtained in not only undrawn sheets but also in drawn sheets of both PCL and PCL/CaCO₃ compounds. Besides, structural change occurred at only drawn PCL/CaCO₃ sheets. Therefore, the change in dynamic mechanical properties observed only for drawn PCL/CaCO₃ sheets were strongly dependent on the orientational structure, which was formed under shear stress of the stretching drawn process. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2376–2382, 2001     

Solid state polymerization of bis(trichlorophenoxo) cobalt(ii) complex to give poly(dichlorophenylene oxide)

Synthesis of four-coordinated (tetrahedral) trichlorophenol cobalt(II) complex with neutral ligand pyridine was achieved from the aqueous solution and its characterization was performed by UV-visible, IR spectral and CHN analysis. Solid state thermal polymerization of the complex was accomplished first at constant temperature employing different time intervals and secondly at constant decomposition time. The poly(dichlorophenylene oxide)s so synthesized were characterized by IR, ¹H NMR and ¹³C NMR spectral analysis, T_g determination, as well as measurement of molecular weight by a viscometric method.