聚氟乙烯树脂的结构与性能研究

对2种不同牌号的PVF树脂进行分析,发现PVF树脂形貌规则,呈球形,树脂中氟原子存在5种不同结构;树脂的熔点和熔融焓随树脂牌号不同而改变;树脂热稳定性好.     

聚乙烯醇缩醛类树脂应用新领域

一、概述聚乙烯醇缩醛类树脂包括聚乙烯醇缩甲醛(PVF)、聚乙烯醇缩丁醛(PVB)、混合缩醛、缩糠醛、缩巴豆醛等等,其中迄今用途最广的是 PVB 和 PVF。缩醛类树脂都是合成粘合剂工业材料之一,具有精细化工的特点:发展快、产量小、质量高、品种多、牌号多。生产厂、以中小企业为主,专业厂少兼生产厂多。与其它粘合剂工业一样,是整个化学工业中最分散的一个行业。     

潜溶剂对聚氟乙烯熔融挤出成型的影响

选取N,N-二甲基甲酰胺、N,N-二甲基乙酰胺和γ-丁内酯作为潜溶剂,分别加入聚氟乙烯(PVF)树脂中改善其加工性能。研究了不同潜溶剂及其用量对PVF树脂的热力学性能、流变性能与制品力学性能的影响,分析了潜溶剂与PVF树脂的相互作用,评价了潜溶剂在PVF树脂熔融挤出成型中的作用,获得了适宜的改性配方和成型工艺。     

ASA在建筑领域的应用研究进展

综述了丙烯腈-苯乙烯-丙烯酸酯三元共聚物在建筑领域的应用研究进展。在合成领域，需要进一步改进合成工艺，发展具有特殊用途的新牌号；在树脂性能研究领域，进一步加强新牌号树脂及共混合金综合性能研究；在应用领域，需要不断拓宽应用领域，降低加工成本，提高产品性能。     

PVF树脂改性玉米淀粉粘合剂的研制

制备了 PVF树脂改性玉米淀粉复合淀粉胶 ,讨论了淀粉的醚化、氧化及 PVF树脂用量等因素对复合淀粉胶性能的影响     

ABS树脂的海内外市场分析（上）

分析了ＡＢＳ树脂的海内外市场情况，既世界市场对ＡＢＳ树脂的需求上升；支柱产业推动了ＡＢＳ树脂的发展和消费；东亚地区ＡＢＳ树脂的发展和消费。我国ＡＢＳ树脂的生产现状和进出口情况，国内ＡＢＳ树脂供应的品种和牌号，合资情况，价格走势以及今后发展的重点。     

聚氯乙烯树脂及配混料的牌号发展动向

以信越及ICI公司为例,叙述国际上大多数重要的聚氯乙烯制造商都重视开发树脂及配混料的品种牌号。这两个厂商按分子结构、用途及聚合方法各自开发了数十种树脂牌号。此外,他们按各种具体用途及加工方法,以高档牌号为代表,细分成不同档次,开发了上百种(或者上千种具有不同色标)配混料牌号,形成许多系列组成一个配混料的大家族。     

PVC医用软管表面晶点产生原因及其解决措施

在对2种不同牌号1000型聚氯乙烯(PVC)树脂性能对比基础上,提出了PVC树脂的"假鱼眼"是造成PVC医用软管表面晶点的主要原因,通过对比这2种牌号PVC树脂的基本性能、增塑剂吸收速率、颗粒的内部结构和外部形态,找出了"假鱼眼"的形成因素,总结了在PVC树脂加工过程中减少晶点的措施。     

羧基硅树脂

ＤｏｗＣｏｒｎｉｎｇ正在推出一种１００％的羧基硅树脂，可作为粘接用树脂或粉末涂布用树脂。这种牌号为ＤｏｗＣｏｒｎｉｎｇ１－０６１９的树脂可与溶剂型硅树脂共混以减少挥发性有机物的产生；也可与溶剂型有机树脂共混，或作为粉末涂布用改性剂以增强热稳定性和耐侯性。ＣｈｅｍＭａｒｋＲｅｐ，１９９９，２５６（１９）：３６羧基硅树脂     

PVF树脂的合成及在水基汽车腻子中的应用

水溶性PVF树脂的制备方法及在水基汽车腻子中的应用效果 ,讨论了各种因素对树脂性能的影响。     

Thermal characteristics of poly(ethylene terephthalate) fiber grafted with poly(vinyl acetate) and poly(vinyl alcohol)

Poly(ethylene terephthalate) (PET) fibers were grafted with poly(vinyl acetate) (PVAc) and poly(vinyl alcohol) (PVA). The effects of graft copolymers PVAc and PVA on morphological properties of PET were evaluated by differential thermal analysis, differential scanning calorimetry, and thermogravimetric analysis. Melting temperature, heat of fusion, and mass fractional crystallinity of PET was not affected by graft PVAc and PVA. No individual glass transition and melting points corresponding to the graft PVAc and PVA were observed, indicating thereby that graft copolymer mainly exists in the form of free chains inside the PET matrix. Poly(vinyl alcohol) graft copolymer degraded at much lower temperatures than poly(vinyl alcohol) in powder form. Thermal stability of PET fiber was not affected by graft PVAc, where as PET–g–PVA showed an additional degradation point at 360°C.     

A differential scanning calorimetry study of plasma irradiation grafting of nascent polyethylene reactor powder

The melting behavior of poly(methyl methacrylate)-grafted nascent polyethylene reactor powder by plasma irradiation was studied by differential scanning calorimetry (DSC). The grafting yield ranged from 11 to 190% Grafting was found to lower both melting point and heat of fusion during the first run of DSC determination. The heat of fusion was used to calculate the apparent grafting yield of the samples. There was little strain induced by plasma-irradiated grafting on the surface of the polyethylene crystals. A method to determine the covalent grafting yield in the graft copolymer systems was developed. © 1995 John Wiley & Sons, Inc.     

Some aspects of the miscibility behavior of polyester/halogenated polymer blends

Glass transition temperature and depression in melting point methods are commonly used to determine the miscibility behavior of polymer/polymer blends, where at least one component of the mixture is semicrystalline. However, these methods often lead to ambiguous and even contradictory results, as can be shown by several examples. Furthermore, a comparison of the miscibility behavior of poly(vinyl chloride), poly(vinyl bromide), and poly(vinyl fluoride) with linear and branched polyesters indicates that small changes in the structure of the halogenated polymer and/or of the polyester lead to major changes in miscibility, indicating the subtle nature of the miscibility phenomenon and emphasizing difficulties in its control.     

Heat‐sealing properties of soy protein isolate/poly(vinyl alcohol) blend films: Effect of the heat‐sealing temperature

To promote the heat‐sealing properties of soy protein isolate (SPI) films applied in the packaging field, we mixed a synthetic polymer of poly(vinyl alcohol) (PVA) with SPI to fabricate blend films by a solution‐casting method in this study. To clarify the relationship between the heat‐sealing properties and the heat‐sealing temperature, strength, melting process, crystalline structure, and microstructure, variations of the heat‐sealing parts of the films were evaluated by means of differential scanning calorimetry, tensile testing, scanning electron microscopy, X‐ray diffraction, and Fourier transform infrared spectroscopy, respectively. The test results showed that both the PVA and glycerol contents greatly affected the melting behavior and heat of fusion of the SPI/PVA blends; these blend films had a higher melting temperature than the pure SPI films. The peel strength and tensile strength tests indicated that the long molecular chain of PVA had a main function of enhancing the mechanical properties above the melting temperature. With increasing heat‐sealing temperature, all of the mechanical properties were affected by the microstructure of the interface between the laminated films including the chain entanglement, crystallization, and recrystallization. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Polymer compatibility: Ternary blends of poly(vinylidene chloride-co-vinyl chloride), poly(vinyl chloride) and poly(acrylonitrile-co-butadiene)

Mixtures of two compatible polymers, poly(vinyl chloride) and poly(acrylonitrile-co-butadiene) containing 40 percent acrylonitrile, can be compatible with poly(vinylidene chloride-co-vinyl chloride), which is incompatible and partially compatible respectively with these two polymers. The crystalline melting temperature and relative heat of fusion of poly(vinylidene chloride-co-vinyl chloride) in blends are higher than those in the pure component. This is attributed to greater ordering of the polymer chains in the crystalline phases of the blends. Replacing the rubber by poly(acrylonitrile-cobutadiene) containing 30 percent acrylonitrile, shows that these three polymers, in which each pair is incompatible or at most partially compatible, also form compatible ternary blends. The crystalline melting temperature is higher and relative heat of fusion lower than those in the pure component. This is attributed to dissolving of parts of the polymer chains originally located in the crystalline phases in the amorphous phases of the blends.     

Intermolecular interactions and phase transition behavior of miscible polymer blends

A linear equation is proposed to quantify the glass transition behavior of miscible polymer blends in terms of the polymer-polymer interaction density parameter whose values are obtainable from the melting point depression method. This practical model is successfully applied to four series of binary polyblends containing poly(hydroxy ether) of biphenol A, poly(vinyl chloride), poly(vinylidene fluoride), and poly(2,4-dimethyl-1,4-phenylene oxide) as the common components. Each of these groups of polymer systems exhibits a distinct type of intermolecular interaction that can be characterized by the two coefficients of the model equation. In connection with the present analysis, three novel expressions are introduced for describing the glass transition temperature—composition relations of the polymer systems of interest.     

Thermodynamic studies of solid polyethers: 5. Crystalline-amorphous interfacial thermal properties

The influence of the crystalline-amorphous interface on the bulk melting phenomena of poly(ethylene oxide) and poly(octamethylene oxide) was studied. For this purpose, heats of solution of various kinds of specimens prepared by precise heat treatment were measured at various temperatures with an isoperibol calorimeter. The crystallinity and the lamellar thickness were determined by dilatometric and small-angle X-ray scattering methods, respectively. Melting points of each sample were determined using a differential scanning calorimeter. The thermodynamic quantities obtained were correlated by theoretical consideration, so that the effects of crystalline-amorphous interfacial thermal properties on bulk quantities such as heat of fusion were derived.     

Melting behavior and surface morphology of poly(vinyl acetate‐co‐vinyl alcohol) copolymer

In a study of the surface morphology of commercial poly(vinyl acetate‐co‐vinyl alcohol) (ACA copolymer) with different percents of hydrolysis, different structures like fibrils, spherulites, micelles, vesicles, and spheroids were seen. The copolymer was crystallized by annealing at two different temperatures. The morphology of the polymer after crystallization and also without crystallization was studied. A decrease in the melting temperature just by heating to the melting temperature was observed, and for a detailed study, repetitive heating of the copolymer was carried out and changes in the mass and heat of fusion after every heating was recorded. The morphology of the copolymer after repetitive heating was studied. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1211–1218, 2002     

Interactions in poly(vinylidene fluoride)/poly(methyl methacrylate-co-ethyl methacrylate) blends

Summary The interaction parameters B for blends of poly(vinylidene fluoride) (PVDF) with poly(methyl methacrylate) (PMMA), poly(ethyl methacrylate) (PEMA) and five methyl methacrylate/ ethyl methacrylate copolymers (PMEMA) were determined by measurements of melting point depression of PVDF. The B values are negative, indicating an attractive intermolecular interaction. The intramolecular interaction parameter between MMA and EMA segments in PMEMA was found to be +3.25 cal/cm³, indicating a repulsive interaction between different monomer segments in the copolymer.     

Study on Thermal Properties and Crystallization Behavior of Blends of Poly(phenylene sulfide)/Poly(ether imide)

The thermal behavior of poly(phenylene sulfide) (PPS) blends with poly(ether imide) (PEI) was studied by differential scanning calorimeter (DSC). The crystallization temperature of PPS in blends shifted from 216.8°C to 226.4°C upon addition of 20–70% PEI contents. The heat of crystallization remained unchanged with less than 50% PEI in blends, whereas the heat of fusion decreased with increasing PEI content. The isothermal crystallization indicated that incorporating PEI would accelerate the crystallization rate of PPS. The activation energy of crystallization increased with addition of PEI. The equilibrium melting point of PPS/PEI blends was not changed with compositions.