NMR研究不同牌号PE-RT和PE100管材的结构北大核心

利用核磁共振波谱仪测试了5种管材专用聚乙烯(记作PE1~PE5),对共聚单体类型、共聚单体和支化点含量进行了分析。结果表明:PE1,PE2,PE3,PE5为乙烯-1-己烯共聚物;PE4为乙烯-1-丁烯共聚物;PE1和PE2的分子链较长且共聚单体和支化点含量较低,有利于形成较厚片晶;PE4和PE5的分子链较短且链结构中有双键结尾的现象;PE3和PE5的主链端甲基含量相同,但PE3中平均每个分子链上的碳数远大于PE5。     

NMR研究不同牌号PE-RT和PE100管材的结构

利用核磁共振波谱仪测试了5种管材专用聚乙烯(记作PE1~PE5),对共聚单体类型、共聚单体和支化点含量进行了分析。结果表明:PE1,PE2,PE3,PE5为乙烯-1-己烯共聚物;PE4为乙烯-1-丁烯共聚物;PE1和PE2的分子链较长且共聚单体和支化点含量较低,有利于形成较厚片晶;PE4和PE5的分子链较短且链结构中有双键结尾的现象;PE3和PE5的主链端甲基含量相同,但PE3中平均每个分子链上的碳数远大于PE5。     

聚乙烯管材料的结构组成及结晶性能

通过傅里叶红外光谱(FTIR)、高温凝胶色谱(GPC-IR)和连续自成核退火分级(SSA)等方法表征了聚乙烯(PE)100级管材料样品的结构及组成,对管材料的微观结构及结晶性能有了进一步的认知。通过GPC-IR表征结果可知,聚合物的支化度随着其中丁烯共聚组成的增加而增加;SSA分级结果表明,高温熔融峰面积占比较高的聚乙烯样品,由于其中形成了较多的厚的片晶结构,是熔融加工中出现晶点的原因。以上分析结果表明,通过调节分子链中的共聚组成,形成适当比例较厚的片晶结构可改善PE管材制品的外观品质。     

固相法涂料用HCPE的聚集态和链结构

研究了固相法涂料用高氯化聚乙烯(HCPE)的结构：以差示扫描量热法表征聚集态结构,以傅里叶变换红外光谱(FTIR)和核磁共振氢谱(^1H-NMR)表征链结构。结果表明,在ω(C1)超过55．00A,时,HCPE中已无晶区存在;FTIR谱图中同时存在表征氯化不均匀的-CH2H2CH2-(γ亚甲基)和-CCl2CH2CHCl-(高频α亚甲基),且有脱HCl反应而生成的C=C振动峰;高频α亚甲基在^1H-NMR中的化学位移为2．80～3．40;随ω(C1)的提高,高频α亚甲基含量显著增加：提高原料PE的粒径或适当提高后期氯化温度,可有效改善氯化均匀度;HCPE清漆中的不溶物主要由隔离剂及氯化程度低的氯化聚乙烯构成。     

泥煤吸附镍前后的傅立叶变换红外光谱

在不同pH下泥煤多次吸附镍,用傅立叶变换红外光谱（FTIR）研究了泥煤与镍元素作用前后的光谱特征．结果表明,pH对泥煤的影响较大;泥煤的红外光谱与腐植酸相似;泥煤与镍元素结合后的红外光谱中归属于1711cm^-1的羧酸二聚体吸收峰减小甚至消失,同时归属于COO^-的1610cm^-1和1410cm^-1处的振动吸收增强,说明泥煤中的羧基与镍离子发生了配合作用,旦大部分是双齿结构．     

红外光谱法定性和定量分析聚烯烃中微量抗氧剂168

研究了用红外光谱法快速测定（聚乙烯、聚丙烯）中微量亚磷酸酯类抗氧剂168的含量，确定了其与固体粉料的混合方式为溶剂混合；分析了抗氧剂168与PE、PP粉料共混的FTIR图，确定了抗氧剂168在PE、PP中的特征吸收峰分别为854cm^-1、1082cm^-1，详细分析了抗氧剂168分别与特定组成的PE、PP、主抗氧剂1010及硬脂酸钙所制样品对所测谱图和所制曲线的影响。根据抗氧剂168的标准曲线可知。抗氧剂168的含量与其特征峰的吸收强度呈良好的线性关系，相关系数达0．96以上，样品中抗氧荆168的回收率高于94．7％。该方法已用于快速定性和定量分析实际样品。     

旋光性和带官能团的三元共聚物--香茅醇、苯乙烯和甲基丙烯酸甲酯的合成与表征及动力学研究

深入研究了一系新型的三元共聚物合成，包括两个给电子单体，即单茅醇（旋光性）和苯乙烯，一个接受电子单体，甲基丙烯酸甲酯，用BPO为自由基引发剂，二甲苯为溶剂，在80℃下反应2h.该体系符合理想动力学特征，总活性自由能为33KJ／mol,用H－NMR分析了三元共聚物的结构，7－8δ的峰为苯基质子峰，3．4－4δ的峰为含甲氧基质子峰，7－7．5δ为乙醇基质子峰，此外，用FTIR光谱分析，在波长2900cm^-1,1750cm^-1和3400cm^-1分别是苯基，甲氧基，和乙醇基的峰，进入共聚物组分的单体通过Kelen-Tudos方法确定，反应比率的值为r1(MMA)=0.9,r2(苯乙烯＋香茅醇）＝0．02。     

红外光谱法定性和定量分析聚烯烃中抗氧剂3114

研究了用红外光谱（IR）法定性和定量分析聚烯烃（聚乙烯、聚丙烯）中的抗氧剂3114的方法和准确度。分析了抗氧剂3114和PE、PP粉料的FTIR图,确定了抗氧剂3114在聚烯烃中的特征吸收峰为1695cm^-1,详细分析了不同含量抗氧剂3114的PE、PP样品的红外谱图和测试的准确度,同时根据抗氧剂3114的标准曲线可知,抗氧剂3114的含量与其特征峰的吸收强度呈良好的线性关系,相关系数达0．97以上,相对百分偏差最大为9．524％。表明红外光谱法可定性和定量分析聚乙烯、聚丙烯中的抗氧剂3114。     

现代仪器分析在聚氨酯中的应用(连载八)核磁共振在聚氨酯结构研究中的应用(三)

3NMR在聚氨酯及其原料定量分析中的应用3．1组成成分定量3.1．1共聚醚中EO与PO的比例氧化乙烯-氧化丙烯（PO-EO）共聚醚分子结构通式为:当R为H时系聚醚H醇;若起始剂为多元醇时得到共聚醚多元醇;R为烷基时系表面活性剂;R为烯基时系匀泡剂的原料。在‘H－NMR谱（溶剂为CDC13）中sl．13处的双峰为PO的甲基峰,设其积分面积为人a32－38处的一组峰为EO中的亚甲峰、PO中亚甲基及次甲基的吸收峰,设其积分面积为见贝uA＝3mpB＝3mp＋4op（l）式中：p为每个质子所占积分面积的数值,。n分别为po及EO的链节数。（D式可转化为下式：m…     

几种医用甲壳素无纺布的红外光谱分析和应用性能比较

文章研究了三种医用甲壳素无纺布的红外光谱和应用性能,结果表明：透射法所得红外光谱吸收峰扁平,不适合甲壳素无纺布的分析;红外反射法不需特别制样,分析在900-1700cm^-1和2800～3600cm^-1处出现了明显和较尖锐的吸收峰,分析方法完全可行：木纤维在1108．9cm。比甲壳素多一个峰,甲壳索在1264．8cm^-1、1587．7cm^-1和1658．2cm。处的峰强度大于木纤维;甲壳素／木纤维复合无纺布在创面模拟中没有出现粘连,手感柔软,颜色较白,更适合医疗敷料用途。     

底座连接口特征参数对显示器后壳注塑质量的影响分析

在Moldflow分析软件的基础上,对显示器后壳进行仿真研究,以翘曲变形量为质量指标,结合控制变量法进行单因素变动实验,保持注射工艺参数不变,研究显示器后壳底座连接口对制品翘曲变形的影响.对数据进行图表分析,结果表明显示器后壳尺寸定位68.58 cm(27英寸)时,底座连接口选用圆形,连接口位置距离底边26 mm,尺寸...     

The role of the symmetry and the flexibility of the anion on the characteristics of the nanostructures and the viscosities of ionic liquids☆

The transport properties of ionic liquids (ILs) are crucial properties in view of their applications in electrochem-ical devices. One of the most important advantages of ILs is that their chemical–physical properties and conse-quently their bulk performances can be well tuned by optimizing the chemical structures of their ions. This will require elucidating the structural features of the ions that fundamentally determine the characteristics of the nanostructures and the viscosities of ILs. Here we showed for the first time that the“rigidity”, the order, and the compactness of the three-dimensional ionic networks generated by the anions and the cation head groups determine the formation and the sizes of the nanostructures in the apolar domains of ILs. We also found that the properties of ionic networks are governed by the conformational flexibility and the symmetry of the anion and/or the cation head group. The thermal stability of the nanostructures of ILs was shown to be con-trolled by the sensitivity of the conformational equilibrium of the anion to the change of temperature. We showed that the viscosity of ILs is strongly related to the symmetry and the flexibility of the constitute ions rather than to the size of the nanostructures of ILs. Therefore, the characteristics of the nanostructures and the viscosities of ILs, especially the thermal stability of the nanostructures, can be fine-tuned by tailoring the symmetry and the conformational flexibility of the anion.     

浅谈设备的性能与操作对胎面压出质量的影响

简要介绍了胎面压出的工作原理及工艺过程，对设备的配置及操作对胎面压出质量的影响进行了分析，并对压出过程中常见的质量缺陷、造成的原因以及解决措施提出了自己的见解。     

Investigation of the effects of fatty acids on the compressive strength of the concrete and the grindability of the cement

In cement industry, a great energy consumption has been observed during grinding of clinker. To reduce this consumption, some waste products have been used as grinding aids.In this investigation, the effects of sunflower oil (SO), oleic acid (OA), stearic acid (SA), myristic acid (MA) and lauric acid (LA) on the fineness and strength of the cement have been examined. These aids were added into clinker in certain ratios based on the cement clinker weight and the grinding has been done for a definite time at the same condition.All of the fatty acids used increased the fineness as compared with the cement without the grinding additives. SO and OA decreased the strength significantly, LA decreased it to a lesser extent and SA increased it definitely according to the common cement. But MA did not alter the strength of the cement as much as SA. In addition, the covering of the balls influences the grinding of cement clinker unfavourably.     

煤粉流动性对GSP气化炉气力输送的影响研究

针对GSP气化装置煤粉气力输送在试车阶段出现的煤粉锁斗下料不畅、发料罐输送性能不佳等问题,从原料煤性质和工业装置的改进方面出发,通过煤粉的流动性参数的测量与研究,分析出现上述工程问题可能的内在原因,并提出工业装置改进方法,为保证GSP煤粉气力输送工业装置的正常运行提供解决办法。     

关于建立火炸药安全数据库的探讨

由反映火炸药及其制品的危险性能和用于对它们的生产、储运系统进行安全评价数学模型出发,探讨了如何建立一个全面、实用的火炸药安全评估数据库。通过对此数据库内容、数据表示方法、数据搜索方法以及建立步骤的讨论,明确了该数据库的使用对象和主要功能。     

The effect of the length of the oxyethylene chain on the conductivity of the polyurethaneurea electrolyte

Polyurethaneureas (PUU), which were synthesized from 4,4′-diphenylmethane diisocyanate (MDI), poly(ethylene glycol) (PEG), and 3,5-diaminobanzoic acid (DABA), were used as polyelectrolytes in this study. Differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FT-IR) were used to monitor the effect of the various kinds of PEG on the changes in morphology of PUU electrolytes corresponding to the concentration of lithium perchlorate (LiClO₄) dopants. The results of DSC and FT-IR indicate the Li⁺ ions coordinate with the soft and hard segments. Additionally, the crystallinity of the PEG soft segment and the ordered hydrogen-bonded urea carbonyl groups decreased with increasing salt concentration. Impedance spectroscopy (IS) measurements show that the PUU electrolyte with the high phase separation degree has the high ionic conductivity. The hard-segment T_g and the soft-segment T_m influence the conductivity behavior of polyelectrolytes with increasing measurement temperature.     

Effect of the drafting force on the strength of the bottom of the spinneret

In spinning basalt fibres, the drafting force is in the same range as in spinning of glass fibres. The effect of the drafting force can not be considered in the calculation for the strength and rigidity of the bottom of the spinneret. __________ Translated from Khimicheskie Volokna, No. 5, pp. 47–50, September–October, 2007.     

转子挤压组合凹模的应力分析

组合凹模的应力分析是一个非常复杂的问题，对其进行精确分析是解决模具寿命的关键。本文采用有限元分析软件Ansys对转子的组合凹模进行了分析，为转子组合凹模的优化设计提供了依据。