聚乙烯醇-壳聚糖/膨润土多孔材料的制备及性能研究

本文以壳聚糖、膨润土、聚乙烯醇为原料,制备了多种复合海绵,并对其吸水倍率,降解印染废水效果以及吸附废水中锌离子的性能进行了探究。研究表明,在聚乙烯醇缩甲醛泡沫中加入壳聚糖或膨润土会使其吸水倍率明显下降。采用聚乙烯醇缩甲醛共混海绵处理模拟染料废水,壳聚糖/膨润土复合海绵效果最好,对酸性橙和艳兰的脱色率分别可达到92%和85%。纯PVA海绵以及单一膨润土共混海绵对锌离子的吸附效果较差,壳聚糖共混海绵吸附效果较好,壳聚糖/膨润土共混海绵吸附效果最佳,可达87.9%。由此说明,在壳聚糖共混海绵中引入膨润土,可以使复合海绵的比表面积进一步增大,提高其吸附效果。     

响应面分析法优化壳聚糖复合海绵的制备工艺

为了确定壳聚糖复合海绵的最佳制备工艺条件,通过单因素实验选取实验因素与水平,根据Box-Benhnken的中心组合实验设计原理,在单因素试验的基础上采用三因素三水平的响应面分析法,依据回归分析确定各工艺条件的影响因子,以复合海绵材料的拉伸强度为响应值作响应面和等值曲线图。壳聚糖复合海绵材料的最佳工艺条件为:电机搅拌速度为541 r/min,透明质酸钠质量分数为14%,壳聚糖与海藻酸钠的质量配比为3.71∶1,得到理论拉伸强度为0.1652 MPa,实际拉伸强度为0.1709 MPa。通过响应面分析法确定了壳聚糖复合海绵的最佳制备工艺,表明该海绵材料具有均匀的多孔与多层次的结构,吸水、保水性能均良好。     

壳聚糖/海藻酸钙微胶囊的通透性能

以传统细胞培养的重要碳源葡萄糖与柠檬酸、氮源L-谷氨酸为小分子模型,以聚乙二醇为测定微囊膜截留相对分子质量的模型分子,研究了微胶囊通透性能,考察了制备条件对壳聚糖/海藻酸钙微胶囊通透性能的影响.结果说明:葡萄糖、柠檬酸和L-谷氨酸可以自由透过微囊膜扩散;采用20 mg/mL海藻酸钠溶液与相对分子质量5万、2 mg/mL壳聚糖溶液制备微胶囊,胶囊的截留相对分子质量为1500;降低成膜壳聚糖溶液浓度和壳聚糖分子量,增大微胶囊粒径均有利于提高壳聚糖/海藻酸钙微胶囊的通透性.     

海藻酸-壳聚糖复合海绵的制备与性能研究

为了制备出结构相对均匀的海藻酸-壳聚糖(ALG-CS)复合海绵(AC),文中采用海藻酸(ALG)发泡液与壳聚糖(CS)发泡液复合的方法以避免复合过程中聚电解质复合物团聚现象。分别对AC的表观结构、溶胀动力学以及黏度、吸液率、保液率和力学性能进行了测定。实验结果表明:ALG/CS发泡液体积比(10∶1)—(2∶1),复合发泡液黏度变化不大,可获得孔结构相对均匀的复合海绵;复合海绵的溶胀过程符合Schott二级溶胀动力学模型;随壳聚糖含量增加,复合海绵吸液率下降,拉伸强度提高,同时可提高复合海绵抗溶剂性能;AC6复合海绵溶胀速率较低,保液率高,这可能与其刚性较强有关。     

胶原蛋白/壳聚糖共混材料的制备及性能研究

将壳聚糖醋酸溶液与胶原蛋白溶液按一定比例共混制备出一系列胶原蛋白/壳聚糖共混材料,对共混材料进行结构表征,并研究了胶原蛋白/壳聚糖共混溶液的粘度,以及胶原蛋白/壳聚糖共混材料的吸水性能、和断面微观形貌。实验结果表明,胶原蛋白和壳聚糖之间有较强的相互作用,随着壳聚糖含量的增加,共混材料的粘度逐渐减小,吸水率逐渐增加,共混膜的玻璃化转变温度比胶原蛋白和壳聚糖的玻璃化转变温度都低,断面脆性较大。     

季铵化壳聚糖止血海绵制备工艺的研究

以表观特征及吸水率为考察指标,探究不同因素对季铵化壳聚糖止血海绵制备工艺的影响。以季铵化壳聚糖为原料,戊二醛为交联剂,采用冷冻干燥工艺制备安全的止血海绵医用生物材料。该方法制得的止血海绵呈雪白色,质地柔软、均匀,结构疏松多孔,且具有一定的弹性。该止血海绵可在酸性、中性和碱性条件下制备,在中性条件下制得的止血海绵吸水率最大;中性条件下,分别考察了戊二醛浓度、温度及季铵化壳聚糖浓度对吸水率的影响,结果表明,当戊二醛质量分数为1.5%,温度为35℃,季铵化壳聚糖质量分数为3%时,制备的止血海绵吸水率最高。所研制的止血海绵安全、稳定,可为季铵化壳聚糖止血海绵的进一步应用研究与临床开发提供实验依据。     

CaCO_3添加量对原位改性纳米CaCO_3/壳聚糖复合涂膜理化性能的影响

以壳聚糖为涂膜基质,采用原位改性法制备了纳米CaCO_3/壳聚糖复合涂膜,考察了纳米CaCO_3质量分数对复合涂膜理化性能的影响。结果表明,添加纳米CaCO_3可以显著提高壳聚糖涂膜的拉伸强度和断裂伸长率,提高其对O_2和水蒸气阻隔能力,降低CO_2阻隔能力。当纳米CaCO_3的质量分数为1.5%时,纳米CaCO_3/壳聚糖复合涂膜的理化性能最佳。     

生物大分子接枝改性丙纶非织造布研究

采用低温氧气等离子体处理聚丙烯(PP)非织造布,利用交联剂将处理后的PP非织造布与生物大分子壳聚糖或胶原蛋白进行接枝反应,探讨了接枝反应条件及改性PP非织造布的性能。结果表明:在环氧交联剂的架桥作用下,等离子体处理后的PP非织造布可接枝壳聚糖或胶原蛋白,适宜的接枝反应条件为0.1 g交联剂,45℃下12 g/L壳聚糖溶液中反应8 h,或35℃下15 g/L胶原蛋白溶液中反应6 h;经氧气等离子体处理后,PP非织造布表面引入了大量的羟基和羧基,并参与接枝反应,壳聚糖的接枝效果优于胶原蛋白;接枝改性后PP非织造布的亲水性、染色性、抗菌性及伤口愈合能力均得到提高。     

稀土-壳聚糖复合絮凝剂印染废水处理应用研究

利用稀土-壳聚糖复合絮凝剂处理印染废水。探讨了复合絮凝剂处理印染废水的处理工艺及最佳处理条件,研究了复合絮凝剂使用时稀土和壳聚糖的浓度、pH值及温度对印染废水处理的去浊率、COD去除率、脱色率的影响。采用正交实验结合单因素实验的方法进行实验,结果表明:复合絮凝剂处理印染废水的最佳条件:稀土-壳聚糖复合絮凝剂浓度为1.5 g/L,反应pH=9,温度为35～45℃。     

复合絮凝剂对染料废水的脱色作用

用羧甲基壳聚糖(CMCTS)复合聚合氯化铁(PFC)对相对分子质量较小的活性染料模拟废水进行脱色处理.结果表明,引入PFC作为助凝剂的脱色效果优于单纯使用CMCTS.采用此复合絮凝剂处理染料废水的最佳条件为pH=5,CMCTS和PFC的投加质量浓度分别为90 mg/L和2 mg/L.在此优化条件下,染料废水的脱色率可达93.8%,COD去除率达89.6%.     

异山梨醇与碳酸二甲酯两步法合成聚碳酸酯的工艺

研究了以碳酸铷（Rb₂CO₃）和乙酰丙酮锂（LiAcac）为催化剂,异山梨醇（IS）和碳酸二甲酯（DMC）为原料合成聚碳酸酯（PC）的工艺过程。优化了酯交换反应催化剂用量、原料配比、缩聚反应催化剂用量、缩聚反应温度以及缩聚反应停留时间,并对酯交换产物和聚碳酸酯产品进行了红外光谱、核磁氢谱、核磁碳谱和热重分析,得到较优工艺条件为：Rb₂CO₃用量1×10^-3mol/mol_IS、原料配比n(DMC)/n(IS)=14、LiAcac用量2×10^-3mol/mol_IS、缩聚温度225℃、缩聚停留时间4h,所得的PC产品特性黏数可达36.55mL/g,数均分子量（M_n）为30659,重均分子量（M_w）为42551,M_w/M_n为1.39,色差为6.92,玻璃化转变温度（T_g）为155.6℃。     

玉米芯木聚糖的提取及其相对分子质量分布研究

通过碱性过氧化氢溶液提取玉米芯半纤维素，单因素试验结果表明：在1% H₂O₂、5% NaOH的碱性过氧化氢溶液中，反应温度50℃、反应时间16 h、液固比为20：1（mL：g），木聚糖得率可达83.15%。采用梯度乙醇分级沉淀法进行半纤维素的分离实验，考察了真空冷冻和烘干方式对产物性能的影响。采用高效离子色谱测定半纤维素单糖组成，并用FT-IR、TG、¹H NMR、¹³C NMR和GPC对半纤维素进行分析与表征。结果表明：各级分由木糖、葡萄糖、阿拉伯糖等组成，玉米芯中半纤维素主要由L-阿拉伯糖-（4-O-甲基-D-葡萄糖醛酸）木聚糖构成；支化度（w（阿拉伯糖）/w（木糖））为0.17~0.52，且随着乙醇体积分数的增加而变大。干燥方式对产物的相对分子质量影响很大，真空冷冻干燥的木聚糖重均相对分子质量（M_w）为108 533~197 752，真空干燥的M_w为41 231~47 242；2种干燥方式所得12种级分中，分散系数为1.172~1.517，其中11种产物分散系数小于1.5，为分布均一的低分散度木聚糖。     

Rosin derivatives: novel film forming materials for controlled drug delivery

Two new rosin derivatives (RD-1 and RD-2) were synthesized in the laboratory and evaluated for physicochemical properties, molecular weight (M_w), polydispersity (M_w/M_n) and glass transition temperature (T_g). Plasticizer free films of the derivatives were produced by casting/solvent evaporation method. The surface morphology (SEM), water vapour transmission and mechanical properties (tensile strength, percent elongation and modulus of elasticity) of the films were investigated. The derivatives were further evaluated for pharmaceutical film coating by characterizing the release of a model drug (diclofenac sodium) from non-pariel seeds (pellets) coated with the derivatives. Pellet film coating could be achieved without agglomeration of the pellets within a reasonable operation time. Drug release from the coated pellets was sustained up to 10 h with the two rosin derivatives. These findings suggest the possible application of rosin derivatives (RD-1 and RD-2) for film coating.     

Rheological changes for urethane polymerizations in bulk and in solution

Viscosity rise and extent of reaction were followed during the step growth polymerization of linear and branched urethanes in bulk and in solution. Results indicate that intra-molecular reaction may exist in both linear and branched systems. Adding solvent increases the extent of intra-molecular reaction. The system viscosity was found to correlate with CgM_w, where C is polymer concentration, g is the ratio of branched to linear polymer radii of gyration, and M_w is the weight-average molecular weight.     

Solubility of polyethylene in n-pentane at high pressures

The high pressure solubility of polyethylene standards (M_w = 2100, 16400, 108000 and 420000 and M_w/M_n = 1.14, 1.16, 1.32 and 2.66, respectively) in n-pentane has been studied. Concentrations of up to 15 wt% polymer have been investigated. For each polymer sample and concentration, pressures that are required to achieve single-phase solutions have been determined over a range of temperatures. The solutions are found to all show lower critical solution temperatures. Demixing pressures are observed to depend strongly on the molecular weight of the polymer.     

Polymers of carbonic acid: 13. Polymerization of cyclotrimethylenecarbonate with tin tetrahalides

Polymerizations of cyclotrimethylenecarbonate (TMC) with SnCl₄, SnBr₄ were and SnI₄ were conducted in bulk. The reaction time, the temperature and the monomer/initiator (M/I) ratio were varied, and the influence of these parameters on yields and molecular weights was investigated. Yields above 90% were obtained with all these initiators, but the highest molecular weights (M_w ≈ 1.5 × 10⁵) resulted from SnI₄-initiated polymerizations. SnI₄ has the additional advantage that the polycarbonates were free of ether groups when prepared at moderate temperatures (e.g. 60°C). In contrast, SnCl₄ and SnBr₄ cause partial decarboxylation even at 60°C, and at higher temperatures up to 20 mol% of the carbonate groups may be replaced by ether linkages. Furthermore, mechanistic studies were conducted. SnCl₄ and SnBr₄ form solid 1:2 complexes with TMC at 20–25°C. Infra-red, ¹H and ¹³C nuclear magnetic resonance (n.m.r.) spectroscopies indicate complexation at the carbonyl oxygen. Kinetic measurements of polymerizations in solvents of different polarity suggest cationic polymerization mechanisms. In addition to CH₂---OH, CH₂Cl and CH₂Br end groups were detected by ¹H n.m.r. spectroscopy. The endgroup analyses of reaction mixtures and isolated poly(TMC) support the assumption of a cationic polymerization mechanism.     

聚合植物油脂表面活性剂的制备及其结构与性能

采用环氧大豆油(ESO)为原料,乙酸乙酯为溶剂,四氯化锡为催化剂,通过环氧大豆油的开环自聚,制备聚合环氧大豆油(PESO);再将PESO在碱性条件下水解,洗涤纯化后得到水解聚合环氧大豆油(HPESO)。通过傅里叶红外光谱(FTIR)、核磁共振氢谱(¹H NMR)和凝胶渗透色谱(GPC)对HPESO的结构及分子量分布进行了表征,并对得到的水解聚合环氧大豆油脂肪酸钾盐表面活性剂(HPESO-K)的临界胶束浓度cmc及其表面张力(γ_cmc)、Krafft点(KP)、液体石蜡/水体系的乳化能力(EP)与抑泡及消泡能力(FP)进行了研究。结果表明:HPESO的数均分子量范围为1056～1156g/mol,重均分子量范围为1255～1374g/mol。在水溶液pH值为9～12条件下,HPESO-K的cmc值为0.13～0.41g/L,γ_cmc值为25.6～31.2mN/m。在水溶液pH=9条件下测得HPESO-K的Krafft点为37℃,液体石蜡/水体系中分出10mL水的时间为130s,亲水亲油平衡(HLB)值范围为10～11。     

Homogeneous reverse atom transfer radical polymerization of glycidyl methacrylate and ring-opening reaction of the pendant oxirane ring

The homogeneous reverse atom transfer radical polymerization (reverse ATRP) of glycidyl methacrylate (GMA) was carried out in bulk, using 2,2′-azobisisobutyronitrile (AIBN) as the initiator and N,N-n-butyldithiocarbamate copper (Cu(SC(S)N(C₄H₉)₂)₂) as the catalyst. The polymerization showed typical controlled/‘living’ polymerization behavior, i.e. first-order kinetics, well-controlled molecular weight (M_n) and narrow molecular weight distribution (M_w/M_n). ¹H NMR and IR spectra showed that the pendant epoxy groups in PGMA polymer remained intact throughout the polymerization of GMA. A phosphorated PGMA (PPGMA) polymer was obtained by phosphonation reaction of the pendant epoxy groups in PGMA with diphenylphosphinic chloride (DPPC). Thermal behavior of the PPGMA was studied by TG and DTG. A major DTG peak at 340 °C was observed for the PPGMA.     

Preparation of high viscosity thermoplastic phenol formaldehyde polymers for application in reactive extrusion

This work deals with the synthesis of high molecular weight, thermoplastic phenol formaldehyde (PF) resins for the application in the synthesis of polypropylene–PF compatibilizers by reactive extrusion. Phenol formaldehyde of high molecular weight is required in reactive extrusion with most polypropylene grades to meet the viscosity ratio (λ) requirement for best mixing. Special lab-grades of PF were therefore developed. The polymers synthesized were highly linear and in the M_w range of 10–30 000 g mole⁻¹.     

螺环二醇改性PET共聚酯的合成及性能

为了扩大聚对苯二甲酸乙二醇酯（PET）的应用范围,常通过引入第三单体来改变其性能。本研究以螺环二醇（SPG）为原料,采用酯交换法熔融缩聚合成了一系列不同单体含量的共聚酯。采用超高效聚合物色谱-多角度激光光散射仪（APC-MALLS）联用分析了共聚酯的分子量与分子量分布,利用核磁氢谱（¹H NMR）、傅里叶红外光谱（FTIR）研究了共聚酯的化学结构,同时采用差示扫描量热仪（DSC）、热重分析仪（TGA）和X射线衍射仪（XRD）研究了共聚酯的热性能以及结晶性能,测试了共聚酯的拉伸性能。结果表明,成功合成了符合纤维级聚酯数均分子量（M_n）和重均分子量（M_w）要求的共聚酯,分子量分布较窄,随着第三单体含量的增加,玻璃化转变温度从77℃提升至85℃,而熔融温度从255℃降低至222℃,热分解温度无明显变化,结晶性能下降。