聚甲基倍半硅氧烷的合成

以甲基三氯硅烷（CH3SiCl3)为主要原料，乙二胺为梯形控制剂，合成了聚甲基倍半硅氧烷，讨论了梯形控制剂，水解介质，催化剂，单体浓度，温度等因素对聚合物摩尔质量及结构规整性的影响，筛选出较佳的梯形控制剂和聚合条件。结果表明：nCH3SCl3:n乙二胺为1：1.1，产物收率接近90%，小解对nCH3SiCl3:nH2O为1：15产物摩尔质量大，且规整性好；水解后，若以四甲基氢氧化铵为催化剂。缩合反应温度为35℃时，若反应时间长，聚合物摩尔质量高，分布宽；反应时间短，则聚合物摩尔质量低，分布窄。若以酸作催化剂，缩合反应温度为80℃时，聚合物摩尔质量较低，分布也较窄。     

微波辐射制备端羟基聚二甲基硅氧烷的研究

在微波辐射下,通过八甲基环四硅氧烷(D4)的阴离子开环聚合反应,制备了端羟基聚二甲基硅氧烷.考察了微波辐射功率、微波辐射时间对聚合反应的影响.采用红外光谱表征了产物的结构;采用气质联用计算产物中存在的混合环体浓度;采用凝胶渗透色谱仪测定产物的摩尔质量及摩尔质量分布.结果表明:初始微波功率设置为700W时,单体的转化率最高,为91.9%.与常规加热法相比,微波辐射下单体的聚合速率和转化率都分别得到了提高,产物中混合环体的浓度较低,产物的摩尔质量分布较窄.     

三元嵌段共聚硅橡胶

四川大学的黄渝鸿等人以八甲基环四硅氧烷、八苯基环四硅氧烷、甲基乙烯基环四硅氧烷为原料，LiOH为引发剂、N，N-二甲基甲酰胺（DMF）为促进剂，采用阴离子开环聚合法，合成了特定结构的三元嵌段共聚硅橡胶，应用真空密炼机进行聚合反应后期的低分子处理，可有效提高共聚橡胶的摩尔质量。可通过调控硅橡胶中基团种类、分布及数量事先对硅橡胶的分子设计。在同等原料配比条件下，     

ATRP合成线性苯乙烯-丙烯腈共聚物

以α-溴代异丁酸叔丁酯(t-BBiB)为引发剂,CuBr/2,2′-联二吡啶(Bpy)为催化体系,在70℃下经原子转移自由基聚合(ATRP)反应进行苯乙烯(St)和丙烯腈(AN)共聚合合成苯乙烯/丙烯腈共聚物。采用GC、~1H NMR和GPC对聚合反应过程和聚合产物进行了分析和表征。结果表明:单体浓度的半对数曲线与聚合时间呈线性关系,聚合物摩尔质量随单体转化率的上升而线性增加,而且摩尔质量分布在1.2～1.3之间,表现出活性聚合反应特征。随着聚合反应的进行,共聚物组成趋向于原始单体组成,大分子链存在梯度结构。     

偏氯乙烯共聚物的单电子转移活性自由基聚合

以碘仿为引发剂,偏氯乙烯和丙烯酸甲酯为单体,连二亚硫酸钠/碳酸氢钠为催化剂体系,羟丙基甲基纤维素和甲基纤维素为分散剂,在水相体系中制备偏氯乙烯共聚物。研究了反应时间、反应温度以及引发剂用量对单体转化率、产物摩尔质量及分布的影响。结果表明,随着反应时间的延长和反应温度的提高,转化率和摩尔质量增加,摩尔质量分布变窄,反应具有活性聚合的特征。使用红外光谱仪(IR)和核磁共振(~1H NMR)对共聚物的结构进行表征并探讨了聚合反应的机理,说明该聚合方法符合单电子转移活性自由基聚合特征。     

高摩尔质量PPR的非等温结晶性能

在工业化聚丙烯装置上生产了高摩尔质量乙烯无规共聚聚丙烯(UHPPR1)，用差示扫描量热仪、广角X射线衍射仪和偏光显微镜研究了UHPPR1和常规摩尔质量PPR(PPR1)的非等温结晶行为、晶体结构和形态，并测试了力学性能。结果表明，UHPPR1的刚性和韧性均较PPR1好。高摩尔质量的分子链起到成核剂的作用，有较快的结晶速率和较高的结晶温度，球晶变小；另一方面，由于UHPPR1的摩尔质量分布宽，其低摩尔质量部分易于结晶，与PPR1有相近的结晶度。     

PMMA的摩尔质量对其介电性能的影响

向塑料光纤纤芯材料纯PMMA中引入链转移剂正丁硫醇（n—BM）以控制摩尔质量。研究了正丁硫醇用量对PMMA介电性能（相对介电常数εr、介质损耗因素、松弛频率fr与体积电阻率ρv）的影响。结果表明，PMMA的介电性能几乎不受影响，同时还发现，PMMA的摩尔质量和摩尔质量分布的变化对其密度影响不大，说明塑料光纤在控制摩尔质量时可以兼顾力学性能与介电性能。     

直接缩聚法合成聚乳酸的工艺改进

以D，L-乳酸为原料，采用优选催化剂、分步除水、连续通氮气、高真空缩合等工艺，直接缩聚合成了可完全生物降解的材料聚乳酸(PLA)。研究了催化剂的种类和用量、聚合温度、聚合时间、体系真空度、聚合工艺等对聚乳酸摩尔质量的影响。最佳条件为辛酸亚锡催化剂0．5份，聚合温度175℃，聚合时间12h，真空度30Pa。改进工艺后合成的聚乳酸无氧化、变色现象，产物的粘均摩尔质量(Mη)达到20800g／mol。     

苯乙烯-丙烯腈-马来酸酐三元共聚物的合成及其在PC/ABS中的应用

采用本体聚合的方法,以苯乙烯、丙烯腈、马来酸酐为反应单体,加入引发剂、链转移剂合成了苯乙烯-丙烯腈-马来酸酐(SAM)三元共聚物.研究了引发剂种类、用量及链转移剂用量对三元共聚物摩尔质量的影响,寻求最优的合成条件;并以自制的SAM来增容聚碳酸酯(PC)/丙烯腈-丁二烯-苯乙烯(ABS)共混物,探讨了SAM对共混物性能的影响.通过红外(FTIR)、核磁(1H-NMR)、差示扫描量热仪(DSC)对三元聚合物结构进行了分析.研究表明:引发剂偶氮二异丁腈(AIBN)效果优于过氧化苯甲酰(BPO),苯乙烯、丙烯腈、马来酸酐物质的量之比为60:38:2,链转移剂十二硫醇(TDM)和引发剂偶氮二异丁腈(AIBN)的用量均为单体总质量的0.1%时,可获得摩尔质量为80 000g/mol左右的三元共聚物SAM;SAM对PC/ABS共混物起到了增容作用.     

ATRP法合成低摩尔质量BPS的研究

采用ATRP法合成了一系列摩尔质量低（Mn=5×10^3～1×10^4g／mol）、分布窄（Mw／Mn=1．8～2．2）的聚苯乙烯（PS）,通过均相催化溴化法制得一系列摩尔质量低、分布窄、溴含量不同的溴化聚苯乙烯（BPS）,其中溴的质量分数最高可达75．59％,热分解温度达396℃。     

高吸水树脂对崩解型聚苯乙烯性能的影响

实验采用乳液聚合法合成了一系列单体组成和吸水倍率不同的高吸水树脂。选取部分吸水树脂与苯乙烯、表面活性剂组成聚合体系，用过氧化苯甲酰引发进行原位共混聚合，制备了遇水崩解型聚苯乙烯。同时，考察了吸水树脂的种类、添加量、吸水倍率和聚苯乙烯的摩尔质量对材料崩解性的影响。研究发现：吸水树脂添加量越大，吸水倍率越高，聚苯乙烯摩尔质量越小，越有利于材料的崩解。当吸水树脂中含有强亲水性基团时，虽然其吸水倍率没有显著提高，但却能明显改善共混物的崩解性。     

Synthesis of star-shaped polymers by coupling reaction between multifunctional core and terminal functionalized polymers

Star-shaped polymers that consist of well-defined polystyrene (PS) arms were successfully synthesized in high yield by coupling reaction between multifunctional core molecules and hydroxyl-terminated PS in the presence of 1, 3-dicyclohexylcarbodiimide and 4-(dimethylamino) pyridine at room temperature. Several systems were investigated: (1) Pyromellitic dianhydride (PMDA) and hydroxyl-terminated PS (PS-OH) with narrow molecular weight distribution, which was prepared by atom transfer radical polymerization (ATRP) of St with 2-hydroxyethyl bromoisobutylate (HEBiB) as initiator. (2) PMDA and PS-OH prepared by conventional free radical polymerization, with 2-mercaptoethanol as chain transfer agent. (3) Narrow molecular weight distributed alternating copolymer of maleic anhydride (MA) and styrene (St), which was obtained via reversible addition fragmentation chain transfer polymerization (RAFT) process, and PS-OH obtained by ATRP. The formation of star-shaped PSs was confirmed by proton nuclear magnetic resonance (¹H NMR) and gel permeation chromatography (GPC).     

Effects of molecular weight distribution on the spinodal temperature of polymer mixtures

The effects of molecular weight distribution on the phase stability of polymer mixtures were explored theoretically and experimentally. Based on the lattice‐fluid theory and volume‐fluctuation thermodynamics, the spinodal conditions for a lattice‐fluid mixture of two polymers with molecular weight distribution were derived. The results indicated that the phase stability of a polymer mixture decreases by increasing the molecular weight distribution of polymers in the blend. To confirm the theoretical results with experiments, the changes in the spinodal temperatures of poly(ethyl methacrylate)/polystyrene (PEMA/PS) blends and tetramethyl polycarbonate/polystyrene (TMPC/PS) blends were examined when each component has a different molecular weight distribution. When the weight‐average molecular weight of each component is the same, a blend composed of polymers having broad molecular weight distribution always exhibited lower phase separation than that composed of polymers having narrow molecular weight distribution at the same blend composition. Copyright © 2004 Society of Chemical Industry     

乳液聚合法制备单分散性PS磁性微球的研究

用改进的乳液聚合法,以乙醇／水为反应介质,十二烷基苯磺酸钠为乳化剂,过硫酸钾为引发剂,制备出单分散性聚苯乙烯磁性微球。通过SEM观察其表面形貌、粒径大小及分布,表明具有良好的球形度和一定均匀性。为了制备出粒径小、粒径分布均匀的聚苯乙烯磁性微球,设计了正交实验来优化实验条件;探讨了反应聚合温度、引发剂用量、乳化剂用量及醇水比对微球粒径及粒径分布的影响。实验表明在实验范围内,较低的反应温度、较低的引发剂用量、较高的乳化剂用量、较低的醇水比有利于得到小粒径、高均匀性的PS磁性微球。     

Macromonomers having different molecular weights of polyethylene glycol and end group functionalities in dispersion polymerization of styrene

Bifunctional polyurethane-based macromonomers (BPUM) were synthesized from various molecular weights of polyethylene glycol (PEG) and hexamethylene diisocyanate (HDI) with different end group functionalities. The synthesized BPUMs were applied to the dispersion polymerization of styrene in ethanol. Structures of various macromonomers and PS particles were investigated using ¹H NMR. Molecular weights of PEG 1000, 2000, 4000, and 8000 were able to provide stable particles of polystyrene (PS), whereas PEG 400 was not big enough to form stable particles. Although the final conversion was almost constant, average size of the PS microspheres increased with PEG molecular weights. The inverse relationship between the size of particles and molecular weight of PS was observed. In particular, the particle size based on the monomers derived with acrylamide was larger than acrylate derivative monomers. As the molecular weight of PEG increased, the thermal stability was enhanced and leveled off. The grafting ratio of the PS calculated from ¹H NMR spectra exponentially decreased from 1.05 to 0.18 mol% with the increased molecular weight of PEG. Thus, present study suggests that the bifunctional macromonomers act not only as reactive stabilizers, but also as grafting agents in dispersion polymerization.     

Grafting of poly(methyl methacrylate) or polyacrylonitrile onto polystyrene using ATRP technique

One of the most useful methods for synthesizing the graft and well‐defined copolymers is the atom transfer radical polymerization (ATRP) method. The polymerization was initiated by polystyrene (PS) carrying chloroacetyl groups as macroinitiator, in the presence of copper chloride (CuCl) and bipyridine (bpy). The macroinitiator (chloroacetylated PS) was prepared by successive chloroacetylation of PS under mild conditions and these reaction conditions overcome the problem of gelation and crosslinking in polymers. Successful graft copolymerizations were performed with methyl methacrylate (MMA) in toluene at 80°C and with acrylonitrile (AN) in tetrahydrofuran/ethylenecarbonate (62.5/37.5 v/v %) mixed solvent at 55°C. The characterization of the copolymers was investigated by ¹H‐NMR and FT‐IR spectroscopices. Gel permeation chromatography measurement indicated an increase of the molecular weight of the graft copolymers, as compared to that of the macroinitiator. This measurement also indicated the monomodal molecular weight distribution. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2619–2627, 2006     

XPS专用料PS 680X的研制与开发

利用5万t/a聚苯乙烯装置开发挤塑聚苯乙烯泡沫塑料(XPS)板材专用料PS 680X,确定了树脂的合成工艺,并对树脂的物理力学性能和加工性能进行了表征。结果表明:PS 680X具有较高的分子量和适当的分子量分布范围,综合性能优良,适合于XPS的生产要求。     

Synthesis and characterization of cross-type vinylurethane macromonomer (C-VUM) and their application in the dispersion polymerization of styrene

The cross-type vinylurethane macromonomers (C-VUMs) were successfully synthesized using trimethylolpropane (TMP) as a cross-agent, and applied to the dispersion polymerization of styrene in ethanol. The existence and the structural identification of the reactants and the products were verified using the FT-IR and ¹H NMR spectra. The molecular weight of C-VUM increased, but the polydispersity index of C-VUM decreased with that of PEG. Structural verification of PS spheres synthesized from C-VUMs is carried out using ¹H NMR. However, the molecular weight of polyethylene glycol (PEG) in C-VUM does not affect the particle size of the PS particles, whereas enhanced the uniformity of the PS particles. Thus, C-VUMs act not only as reactive stabilizers, but also as grafting agents     

纤维素/NMMO/水溶液流变性能的研究

研究了不同聚合度的纤维素/NMMO/水溶液以及在添加剂NH_4Cl存在下的溶液的流变性能,并将流变性能与纺丝性能进行对照分析,此外,还通过动态流变实验的分析比较了不同纤维素浆粕的相对分子质量及其分布。     

Cloud point curves for poly(vinyl methyl ether) and monodisperse polystyrene mixtures

The compatibility behaviour of poly(vinyl methyl ether) (PVME) and monodisperse polystyrene (PS) is studied for solution cast films. The molecular weight of monodisperse PS ranges from 2100 to 2 000 000 whereas the PVME used is polydisperse and has weight-average molecular weight of 51 500. When cast from toluene solution, the mixtures undergo phase separation at elevated temperatures. The cloud point curves move to markedly lower temperatures with increasing molecular weight which is similar to the lower critical solution temperature (LCST) behaviour for polymer solutions. They move to lower temperatures until the molecular weight of PS reaches about 51 500.The effect of molecular weight distribution on the cloud point of equal amounts of PS and PVME mixtures simulated by mixing two monodisperse polystyrenes of different molecular weight for PS part is accurately predicted by using weight-average molecular weight for PS in this range. However, if the molecular weight of PS exceeds about 110 000 the molecular weight dependence of cloud point temperature is reversed and the prediction for polydisperse polymer by using weight-average molecular weight fails. This phenomenon is discussed from several viewpoints including the possibility of the effect of chain entanglement.Mixtures of PVME and PS of M_w = 20 400 were also cast from an ‘incompatible’ solvent, trichloroethylene. Compatibility is found to be dependent on composition and even phase-separated samples show at least one cloud point, indicating at least partial mixing of the two polymers. Finally, it is demonstrated that crosslinking of compatible films can be achieved by electron irradiation to form true interpenetrating networks. The cloud point temperatures are increased drastically after crosslinking.