BARRIER PROPERTIES OF VINYLIDENE CHLORIDE/METHYL ACRYLATE COPOLYMER

A series of vinylidene dichloride (VDC) copolymers with methyl acrylate (MA) ascomonomer (3--12wt%), was prepared by free-radical suspension copolymerization. Thepermeability coefficients of the copolymers to oxygen and carbon dioxide were measured at1.0 MPa and at 30℃, and those to water vapor were measured at 30℃ and 100% relativehumidity All the VDC/MA copolymers studied are semicrystalline. As the MA contentincreases, the permeability coefficients of the copolymers to oxygen, carbon dioxide, andwater vapor are progressively increased, caused by decrease in crystalline fraction andincrease in free volume of VDC/MA copolymers.     

偏氯乙烯-氯乙烯悬浮共聚物的结晶与熔融性能

研究了聚合温度、共聚物组成、低分子助剂用量等对偏氯乙烯 (VDC) 氯乙烯 (VC)悬浮共聚树脂的结晶度、熔融峰温度的影响 ,并用Florry的聚合物熔点降低理论预测共聚树脂熔点随共聚组成、低分子助剂用量的变化规律 ,为VDC VC悬浮共聚树脂的合成工艺条件和加工性能的改善提供理论基础 .     

THE EFFECT OF MONOMERS FEEDING METHODS ON EMULSION COPOLYMERIZATION OF VINYLIDENE CHLORIDE AND ACRYLATES

The emulsion copolymerization of vinylidene chloride (VDC) with methyl-methacrylate(MMA) and acrylonitrile (AN) was carried out by batch, seeded batch and semicontinuous pro-cesses,respectively. Significant differences were found in the physical and mechanical propertiesof the latexes and films, depending on the methods of monomer feeding. The results both intheory and experiments demonstrated that the copolymer composition and the length of the VDC sequences in the copolymer could be controlled by the modes of monomer feeding process.     

供体-受体型共轭聚合物电子结构和导电性能的理论设计

以苯并[1,2-c:4,5-c']二[1,2,5]噻重氮和吡嗪并[2,3-g]喹喔啉为电子受体(A),噻吩、噻吩并[3,2-b]噻吩和二噻吩并[2,3-b:2',3'-d]噻吩为电子供体(D),设计了6种D-A型共轭聚合物.采用B3LYP方法,研究了这6种聚合物的几何结构和电子性质.D-A型共轭聚合物的几何结构和电子结构与电子供体和电子受体的性质,特别是与其提供电子和接受电子的能力密切相关.聚合物的能隙主要受键长交替控制,键长交替越小,能隙越窄.所设计的6种聚合物中,p-BBT-TT具有较窄的能隙(0.48 eV)、较小的载流子有效质量和相对较大的能带宽度,具备理论上的良好导电性能,可能是潜在的优良导电聚合物材料.     

偏氯乙烯-丙烯腈悬浮共聚物的组成研究

研究了偏氯乙烯 丙烯腈 (VDC AN)悬浮共聚体系中AN的水溶性对单体相组成和树脂组成的影响 .结果表明 :由于AN部分地溶于水 ,使有机相AN的含量降低 ,导致共聚树脂的组成明显地不同于本体聚合模型的计算预测值 .为了准确地计算预测VDC AN共聚树脂的组成 ,本文假设溶于水的AN向有机相迁移的速度比聚合反应速度快得多 ,AN在两相的溶解分配近似为平衡态 .计算中先用描述AN在VDC/水系统中溶解分配的Marker式校正有机相AN的含量 ,然后根据校正后的AN含量用Mayo Lewis式计算预测VDC AN悬浮共聚物的组成 ,计算中有关的竞聚率值取自于文献中本体聚合的值 .计算结果与实验值一致     

偏氟乙烯-三氟氯乙烯共聚物链结构的研究

用裂解气相色谱-质谱法(Py-GC/MS)研究了单体克分子比近于1:1的偏氟乙烯-三氟氯乙烯共聚物(F23)链结构。采用了居里点裂解器和裂解探针。质谱的鉴定结果表明,两种裂解器在一定条件下得到的F23裂解产物非常相似。根据这些裂解产物的化学结构,可以推断F23中两种单体的键接方式,并确定F23中占优势的链段排列为:(?)     

ANTIFOULING PROPERTIES OF POLYVINYL CHLORIDE) MEMBRANES MODIFIED BY AMPHIPHILIC COPOLYMERS P(MMA-A-MAA)

Three well-defined diblock copolymers of poly(methyl methacrylate-b-methacrylic acid)(P(MMA-b-MAA))were synthesized using atom transfer radical polymerization method and varying poly(methacrylic acid)(PMAA)chain lengths. These copolymers were blended with PVC to fabricate porous membranes via phase inversion process.Membrane morphologies were observed by scanning electron microscopy(SEM),and chemical composition changes of the membrane surfaces were measured by X-ray photoelectron spectroscopy(XPS).Static and dynamic protein adsorption experiments were used to evaluate antifouling properties of the blend membranes.It was found that,the blend membranes containing longer PMAA arm length showed lower static protein adsorption,higher water permeation flux and better protein solution flux recovery.     

甲基丙烯酸-苯乙烯嵌段共聚物的XPS研究

对甲基丙烯酸-苯乙烯嵌段共聚物DMF溶液涂制膜(接着经过或不经其它溶剂的处理)的XPS研究表明,共聚物本体组成对膜的表面组成没有明显的影响。从DMF溶液直接涂膜时,按照两相模型,PMAA在表面的面积分数最大可达0.55。在用溶剂处理时,膜表面组成基本上决定于所用溶剂的溶解度参数,PMAA的表面面积分数按下列顺序降低:水>乙醇>环己烷>石油醚。     

偏氟乙烯-四氟乙烯共聚物高取向薄膜的形态结构研究

聚偏氟乙烯(PVF₂)至少有四种晶相结构,即α、β、γ和δ相,PVF₂的压电性和热电性直接依赖其β相结构。 本工作报导以特殊的熔体拉伸方法制备不同组成偏氯乙烯(VF₂)和四氟乙烯(VF₄)的共聚物高取向薄膜与对其结构的研究结果。     

PREPARATION AND SURFACE PROPERTIES OF ACRYLIC COPOLYMERS CONTAINING FLUORINATED MONOMERS

A series of copolymers comprising butylmethacrylate, styrene, butylacrylate, hydroxypropyl acrylate and perfluoroalkyl methacrylate were synthesized by the free radical polymerization using BPO as an initiator. The surface property of the copolymer films was subsequently characterized. The contact angle measurements and energy dispersive analysis of X-ray （EDAX） show that the length and content of perfluoroalkyl side chains in the copolymers are crucial for the preparation of the film with low surface energy. At a given content of fluorinated monomers in the copolymers, the longer the perfluoroalkyl side chain, the larger the water contact angle of the copolymer films will be. On the other hand, the higher the content of fluorinated monomers, the lower the surface energy is. The water contact angle increases with the increase of the fluorinated monomer content and reaches a plateau at 3 wt% of fluorinated monomer content.     

关于聚皂共聚物组成的核磁共振研究

烷基甲基二烯丙基溴化铵共聚物是一种新型疏水改性的聚皂,应用多种核磁共振分析技术对其结构和共单体的组成进行了定量的讨论.研究结果表明,在测定化学结构和性质上比较接近的共单体组成时,核磁共振方法是一种有效的工具.     

STUDY ON SOME PROPERTIEE OF Si-CONTAINING POLYESTER-POLYETHER MULTIBLOCK COPOLYMERS

Some physical properties of the polyester-polyeher multiblock copolymers with Si-containing hard segment were further examined by a series of physical methods. Thehydrophobicity of the copolymers was improved with the incorporation of increasing amountof organosilicone, XPS test proved that silicon element was enriched at the surface of theSi-containing polyeser-polyether copolymers. It was also found that their heat resistanceand gas permeability for O_2 and N_2 were greatly improved. The study on semipermeabilityof films made of the Si-containing copolymers was also followed with interest.     

芴-苯并噻二唑-苯胺类共聚物的合成与发光性能

用Suzuki缩聚反应分别将窄带隙单元-苯并噻二唑-二苯胺(DPABT)和苯并噻二唑-三苯胺(TPABT)引入聚芴主链,合成了共聚物PF-DPABT和PF-TPABT,并比较了共聚物的发光性能.随着窄带隙单元含量的增加,其特征发射逐渐增强,说明发生了从聚合物主体单元到窄带隙单元有效的能量转移.两种共聚物在低窄带隙单元含量(1mol%)下的电致发光光谱仅出现窄带隙单元的特征发射,PF-DPABT共聚物为650～680nm之间的饱和红光,而PF-TPABT共聚物为590～610nm之间的橙红光,聚芴主体单元的发射被完全淬灭,说明与光致发光过程相比,电致发光过程中的能量转移更完全.基于共聚物PF-DPABT-1及PF-TPABT-5器件的最大外量子效率分别为1.3%和2.0%,器件结构为ITO/PEDOT:PSS/polymer/Ba/Al,是一类有希望的红光材料.     

高交联大孔苯乙烯-二乙烯苯共聚物的磺化反应

研究了高交联大孔苯乙烯－二乙烯本共聚物在有溶胀剂和无溶胀剂条件下,反应温度、 反应时间及共聚物合成时所用致孔剂对其磺化反应的影响．结果显示,当磺化反应在不同溶胀 剂介质中进行时,共聚物的交换容量随交联度变化可是现不同的关系．与低交联大孔共聚物（交 联度７％）比较,高文联大孔共聚物（交联度６０％）磺化反应速度更快,反应能在低得多的温度下 进行,同时溶胀介质对磺化产物的交换容量的影响变得很小．６０％交联的共聚物于３５Ｃ反应３ｈ, 可获得接近于表面磺化的产物．     

乙烯-丙烯共聚物磺酸盐离聚物的研究——Ⅰ.乙烯-丙烯共聚物及其氯磺化反应

本文用钛系高效催化剂合成了四种乙烯-丙烯共聚物,测定了共聚物的单体组成、序列结构分布、分子量和结晶度.在考察了引发剂和氯磺化试剂对氯磺化反应影响的基础上,制备了不同磺化度的氯磺化乙丙共聚物,并用~(13)C-NMR分析其化学结构,表明共聚物分子链上CH没有发生反应,CH_3只被-SO_2Cl取代,而CH_2可被-SO_2Cl或-Cl取代.     

聚丙烯-聚乙烯嵌段共聚物的分子结构及性能的研究

本工作用核磁共振(~(13)C-NMR)、示差扫描量热(DSC)、动态力学分析(DMA)和扫描电子显微镜(SEM)等技术研究了将丙烯、乙烯单体两步分段共聚、预期为聚丙烯-聚乙烯嵌段共聚物的合成物(简称为聚丙烯-聚乙烯嵌段共聚物或嵌段共聚物)。结果表明,在嵌段共聚物中含有一定量的、能为正庚烷抽提出来的乙丙无规共聚物(EPR);分段共聚的产物并非预想的PP-b-PE两嵌段共聚物,而是含有多种组分的共混物;形态表征的结果表明了嵌段共聚物为多相体系,EPR和PE形成分散相以球形无规分布于PP基体中。     

X-射线光电子能谱研究偏二氯乙烯-丙烯酸甲酯共聚物的光解反应

用X-射线光电子能谱(ESCA)方法研究了偏二氯乙烯-丙烯酸甲酯共聚物(VDC-Co-MA)在大气及惰性气氛下的紫外光解反应,从ESCA信息随光照时间的变化规律探讨了几种可能存在的光化过程;结果还表明其碳-氯键断裂速度比聚偏二氯乙烯(PVDC)快;此外,由于同一碳上氯取代度的不同,使PVDC和PVC在大气环境中的光化反应有明显差别。     

SYNTHESIS AND PROPERTIES OF COPOLYMERS FROM 1-[3,5-BIS(TRIMETHYLSILYL)PHENYL]-2-PHENYLACETYLENE

Copolymerization of 1-[3,5-bis(trimethylsilyl)phenyl]-2-phenylacetylene (m,m-(Me₃Si)₂DPA) with other diphenylacetylene derivatives and their copolymer properties were investigated. Homopolymerization of m,m-(Me₃Si)₂DPA by TaCl₅─n-Bu₄Sn (1:2) did not give the polymer due to steric hindrance. However, m,m-(Me₃Si)2DPA copolymerized with diphenylacetylene (DPA), 1-phenyl-2-[p-(trimethylsilyl)phenyl]acetylene (p-Me₃Si DPA), and 1-phenyl-2-[m-(trimethylsilyl)phenyl]acety-lene (m-Me₃SiDPA) in the presence of TaCl₅─n-Bu₄Sn at various feed ratios to give copolymers in moderate yields. The formed copolymers were yellow to orange solids, which were soluble in common organic solvents such as toluene and CHCl₃. The highest weight-average molecular weights (M_w) of these copolymers reached ca. 6 × 105 and tough films could be obtained by solution casting. Their onset temperatures of weight loss in air were observed around 400°C, indicating high thermal stability. The oxygen permeability coefficients at 25°C of copoly(m,m-(Me₃Si)₂ DPA/DPA) (feed ratio 1:1) and copoly(m,m-(Me₃Si)₂DPA/p-Me₃SiDPA) (feed ratio 1:2) were 21 and 100 barrers, respectively, medium in magnitude among polymers from substituted acetylenes.     

偶氮苯型侧链液晶聚合物的阻隔特性研究

合成了偶氮苯侧链液晶聚合物聚甲基丙烯酸(3-[4-(4′-氰基偶氮苯)苯氧基]丙酯)(PM3ABCN),采用原位掠入射X射线衍射(GIXRD)方法研究了该聚合物膜在向列相和各向同性态(无定形相)时对气体的阻隔特性.并采用X射线能谱仪(EDS)分析铁片氧化后的氧含量,计算得到渗透通过聚合物膜的氧气的量.结果表明,当PM3ABCN膜处于各向同性态时,通过聚合物膜的氧气平均渗透量为1.92×10-3cm3 day-1m-2;而处于液晶态的膜对氧气的阻隔性提高了4.4倍,氧气平均渗透量为4.38×10-4 cm3day-1 m-2.结合样品表面的显微分析结果,探讨了液晶凝聚相结构对气体小分子的阻隔机理.