《高分子化学实验》课程的教学探讨

结合本校实际情况对高分子化学实验课程的教学经验进行了探讨。在高分子化学实验的教学过程中，为充分激发学生学习的兴趣，提高学习的积极性和主动性，提高教学效果与教学质量，实验的内容首先要体现高分子化学理论课程的核心内容——高分子合成；其次实验项目要带有一定的趣味性和应用性;再次实验时间要与理论课程相协调，实验项目的安排顺序要...     

CH自由基和NO2反应研究Ⅰ.反应的热力学计算

探讨了CH自由基与NO2反应的可能路径,通过计算确定了反应物,产物和稳定中间体的电子状态和平衡构型,并运用Gaussian-3方法和MRCISD方法对可能的反应路径进行了热力学计算.在多数情况下与实验值符合较好.对于个别与理论计算差别较大的实验值进行了评述.     

Yb3+在不同基质中基态分裂能的计算分析

利用晶体场理论,推导出Yb3+离子基态(2F7/2)与Nd3+离子基态(4I9/2)最大分裂能之间的关系式为△E(2F7/2)=1.4667△E(4I9/2),从实验数据拟合得到的关系式为△E(2F7/2)=1.0987△E(4I9/2).理论计算与实验拟合存在差异,分析了出现差异的原因,认为差异主要是由相同晶体场对于不同掺杂离子的影响即晶体场参数Nv值不完全相同而引起的.     

应用理论化学方法预测有机分子的标准摩尔生成焓

介绍一个针对高年级本科生开设的计算化学创新性实验,采用高斯理论计算一系列有机小分子的构型和热化学性质,并通过原子化反应法计算其标准摩尔生成焓.该实验可让学生初步掌握相关计算软件的使用,了解不同计算方法的适用范围,认识理论与实验相结合的实践途径.     

溴水与苯酚反应产物的探讨

通过查阅文献和实验探究了苯酚的几种溴代产物在水、苯酚熔液和苯酚水溶液中的溶解性;从有机反应的理论角度探讨了苯酚溴代反应机理及产物的确证,指出苯酚与溴水反应的产物是2,4,6-三溴苯酚。     

CF3CH2CH3+OH的反应机理及动力学性质的理论研究

采用密度泛函理论BB1K/6-31+G(d,p)计算了反应CF₃CH₂CH₃+OH各反应通道上驻点的稳定结构和振动频率, 并分别在BMC-CCSD, MC-QCISD和G3(MP2)水平上进行了单点能校正. 运用变分过渡态理论, 在BMC-CCSD//BB1K, MC-QCISD//BB1K, G3(MP2)//BB1K以及BB1K水平上计算了各反应通道的速率常数, 讨论了-CH₂和-CH₃基团上H提取通道对总反应的贡献, 并与已有实验和理论结果进行了对比. 计算结果表明, BMC-CCSD水平上的速率常数与实验测量值符合得很好, 进而给出了该水平上反应在200~1000 K温度范围内速率常数k(cm³?molecule^-1?s^-1)的三参数表达式: k=1.90×10^-21T^3.21exp(-292.62/T).     

控制卷积量变化的电化学方法理论与应用——伴有后续均相催化反应的电极过程(Ⅱ)

采用电流与时间的卷积作为可控制量的电化学实验方法,对伴有后续均相催化反应的电极过程进行了理论处理,得到了恒半积分法、半积分扫描法和半微分扫描法的理论曲线,并对三氯化铁——双氧水体系进行了实验验证,获得了后续均相催化反应的动力学速率常数,结果与文献值吻合。     

氯水和溴化钾、碘化钾溶液反应现象的探讨

对氯水与碘化钾溶液、溴化钾溶液反应出现的现象通过实验进行了探讨,分析了氯水和KI溶液反应后的溶液用CCl4萃取生成的碘时出现异常现象的原因,提出了做好氯水与碘化钾溶液反应实验的方法。     

3d过渡晶体化学键共价性和光谱位移研究

本文利用ＰＶ理论通过考虑３ｄ电子对晶体化学键的影响,计算了若干３ｄ过渡金属化合物的化学键参数并运用于Ｒａｃａｈ参数和穆斯堡尔谱同质异能位移的研究,计算得到的结果与实验值符合的很好。     

Sb2Te3及其固溶体的电子结构

以Ｓｂ２Ｔｅ３及固溶体材料的制备与测试数据为依据，采用量子化学的理论及近似方法，计算得出材料的电荷分布，态密度，能级等结果，与实验数据基本一致。其结果对材料的研制具有指导意义。     

Polymers with Upper Critical Solution Temperature in Aqueous Solution

This review focuses on polymers with upper critical solution temperature (UCST) in water or electrolyte solution and provides a detailed survey of the yet few existing examples. A guide for synthetic chemists for the design of novel UCST polymers is presented and possible handles to tune the phase transition temperature, sharpness of transition, hysteresis, and effectiveness of phase separation are discussed. This review tries to answer the question why polymers with UCST remained largely underrepresented in academic as well as applied research and what requirements have to be fulfilled to make these polymers suitable for the development of smart materials with a positive thermoresponse.     

绿茶汁鉴别碳酸钠与碳酸氢钠溶液实验及机理探讨

绿茶汁滴入NaHCO3溶液显浅茶色,再滴加稀硫酸颜色不变,有大量气泡产生.绿茶汁滴入Na2CO3溶液显清亮的深茶色,再滴加适量的稀硫酸以后,颜色突然变浅,有大量气泡产生.计算发现,NaHCO3 和Na2CO3溶液的浓度对实验现象基本没有影响.     

硫酸铜与氢氧化钠反应生成碱式盐的研究

通过实验定量研究了NaOH溶液与CuSO4溶液反应生成的沉淀物的组成.结果表明,CuSO4与NaOH反应生成的碱式盐只有Cu4(OH)6SO4;当反应物比例n(OH-)/n(Cu2+)≤1.5时,沉淀为Cu4(OH)6SO4,而当2≥n(OH-)/n(Cu2+)> 1.5时,产物为Cu4(OH)6SO4与Cu(OH)2的混合物,比例越大,Cu4(OH)6SO4含量越少,Cu(OH)2含量越多.在NaOH溶液滴加到CuSO4溶液的过程中,Cu(OH)2是由Cu4(OH)6SO4与OH-之间的反应生成的,且反应缓慢.     

两性高分子的溶液性质

两性高分子是分子链上同时含有正负电荷基团的一类高聚物、具有独特的溶液性质。本文就两性高分子等电点的构象状态、影响等电点的因素、两性高分子的溶解性以及高分子结构和组成、ｐＨ、溶液离子强度、混合溶剂、温度对流体力学行为的影响进行了综述。     

聚丙烯腈溶液的凝胶化研究

聚丙烯腈是用途最广泛的聚合物之一,其溶于适当溶剂中形成的聚丙烯腈溶液是制备聚丙烯腈纤维、渗透膜等高分子材料的原料。聚丙烯腈溶液的物理化学性质对所制备材料的性能有很大的影响。本文对高分子溶液的凝胶化和高分子凝胶的特点做了简要介绍,并介绍了聚丙烯腈及其凝胶的特点。根据高分子浓溶液体系的特点提出用于表征聚丙烯腈溶液凝胶化的主要方法。从浓度和温度对聚丙烯腈溶液凝胶化行为的影响、熟化和非溶剂对聚丙烯腈溶液凝胶化行为的影响、聚丙烯腈溶液凝胶化的热可逆性、聚丙烯腈溶液凝胶化的分形特征以及聚丙烯腈凝胶的交联机理这几个方面对已有聚丙烯腈溶液的凝胶化研究成果和最新进展进行了综述。最后对聚丙烯腈溶液凝胶化和聚丙烯腈凝胶的研究前景做了展望。     

Solution grown polymer crystals

Summary A survey is presented on some front line issues in the field of polymer crystallisation from dilute solution. The major portion of the review is devoted to the discussion of the problem of disorder in the simplest single crystal forms which can be considered as a preliminary for the understanding of the nature and behaviour of the amorphous content in a crystalline polymer. Available evidence for the existence of both disorder and crystallographic regularity along the fold surface is critically reviewed, and the compatibility of theoretical considerations with the various conceivable fold surface models is being analysed. The critical surveying of these issues suggests some obvious ways in which the apparently conflicting claims as regards the nature of the true fold surface could be reconciled, and along which future investigations could be fruitfully conducted. Some exploratory work aimed at the clarification of the disorder problem in single crystals pursued along some new lines in our laboratory is being outlined. In addition, single crystal growth from chemically inhomogeneous molecules (copolymers) is also touched upon.In the second part of the review a brief survey is presented of the research in a newly emerging field concerned with crystals with intrinsically fibrous habit resulting from crystallisation during flow, a topic which opens up new perspectives in the subject of polymer crystals.Finally some rather illuminating pictorial similarities between crystals from solution and the melt are placed in juxtaposition.     

Solution properties of polyoxymethylene

Light scattering and viscosity have been measured at 25°C. for dilute solutions of six unfractionated polyoxymethylene samples in the mixed solvent hexafluoroacetone–water (mole ratio 1/1.7) slightly buffered with triethylamine. Dialysis equilibrium through porous Vycor glass thimbles indicates that the polymer is strongly solvated by the hydrate (CF₃)₂C(OH)₂, and this must be taken into account in evaluating weight-average molecular weights from the light-scattering data. Over the molecular weight range 23,000–185,000, the intrinsic viscosities (in deciliter per gram) follow the relation The corresponding unperturbed dimensions are σ = 2.3 ± 0.2 or r₀²/nl² = 10.5 ± 1.5.