Fully renewable limonene‐derived polycarbonate as a high‐performance alkyd resin

Limonene‐derived polycarbonate‐based alkyd resins (ARs) have been prepared by copolymerization of limonene dioxide with CO₂, catalysed by a β‐diiminate zinc–bis(trimethylsilyl)amido complex, and subsequent chemical modification with soybean oil fatty acids using triphenylethylphosphonium bromide as the catalyst. This quantitative partial modification was realized via epoxy–carboxylic acid chemistry, affording ARs with higher oil lengths, lower polydispersities and higher glass transition temperatures (T_g) in comparison to a conventional polyester AR based on phthalic acid, multifunctional polyol pentaerythritol and soybean fatty acid. The novel limonene polycarbonate AR and the conventional polyester AR were evaluated as coatings and both the physical drying (without the presence of the oxidative drying accelerator Borchi® Oxy Coat) and chemical curing (with Borchi® Oxy Coat) processes of these coatings were monitored by measuring the König hardness and complex modulus development with time. A better performance was obtained for the alkyd paint containing polycarbonates modified with fatty acids (FA‐PCs), which showed a faster chemical drying, a higher König hardness and a higher T_g in coating evaluation, demonstrating that the fully renewable FA‐PCs are promising resins for alkyd paint applications. © 2019 Society of Chemical Industry     

生物降解型聚碳酸顺丁烯二酸亚乙酯 1、合成和表征

用CO_2、环氧乙烷、顺丁烯二酸酐进行三元共聚首次得到聚碳酸顺丁烯二酸亚乙酯(PECM),并用IR、~1H NMR、DSC等进行了表征,共聚物链中CO_2和MA单元随机分布,不饱和单元可在0～0.5mol分数之间调节。共聚过程不发生双键交联和构型转化。环氧乙烷的转化率可高达到93％。控制PECM链上的双键含量并使之发生自由基加成反应,得到对热较稳定的可溶性产物。     

Modeling the continuous melt transesterification of bisphenol-A and diphenyl carbonate in a continuous stirred tank reactor

A model of continuous melt transesterification of bisphenol-A and diphenyl carbonate in a continuous stirred tank reactor is developed using phase equilibria assumption and the method of molecular weight moments. The model equations can be simplified into a polynomial system that has 17 equations and 17 unknowns. Solution of the polynomial system gives out almost every aspects of the continuous transesterification process. Molecular weight and polydispersity index, end group ratio of hydroxyl to phenyl carbonate, contents of molecular species, and lost diphenyl carbonate fractions are studied in different operation parameters.     

Compatibility between Polyamide 6 and Polycarbonate

Polyamide （PA6） and polycarbonate （PC） were prepared by a Brabender mixer （ PLV- 151） at 240℃ with 30 rpm for duration of 8 and 6 minutes respectively. The epoxy resin （E） addition can lead to substantial microstructural changes in the PA6/PC blends. Scanning electron microscope （SEM） was used to observe the mixtures characterized by the domains of clearly segregated homophases and voids between the two polymers. PA6/PC of polyamide 6 and polycarbonate with epoxy resin addition under the composition ratio of 20/80, 20/80/1, 40/60/1 and 40/60, were tested to verify the key role of epoxy in promoting the compatibility of PA6 with PC during blending.     

流水线上机械手克隆转换开关改性塑料的选择

转换开关是用在工业生产自动流水线机械手中一种易磨损和大量消耗的塑料制品,以前依靠外国进口,花费了大量外汇。由于转换开关的精度极高,甚至超过金属件的制造精度。故不仅要求制品在成型加工过程中不能有微小的变形,甚至需要严格控制塑料的收缩量。使得所有成型孔的精度达到IT6级以上,平面度不大于0.02 mm,圆柱度不大于0.01 mm。通过对亚光微珠增强聚碳酸脂改性材料的选择,实现控制了制品变形量和提高了耐磨性的目的,通过超高精度孔的二次限制工艺的实施,使得制品孔的精度可达到IT4级以上,圆柱度为0.002 mm以内。国产转换开关完全取代了进口产品,且其精度和寿命远高于进口产品,为超高精度注射件加工创出了一种新方法,也为有关单位节约了大量外汇。     

熔体温度对气体辅助注射成型PC／PE共混物形态的影响

分别在低温（200℃）和高温（270℃）下制备了聚碳酸酯／聚乙烯（PC／PE）共混物的气体辅助注射成型制品，通过扫描电镜对PC相不同部位的形态观察，发现分散相PC的形变和分布受成型温度的影响比较大。在低温成型时，分散相PC从表层到气道都有变形，而在高温成型时，分散相PC在气道部位几乎没有变形。在形态分析的基础上，探讨了温度对气体辅助注射成型共混物形态的形成和分布的影响机理。     

Magneto-sensitive nickel nanowires fabricated by electrodeposition into multi- and single-ion track templates

Polycarbonate templates of (30±1) μm thickness containing cylindrical etched-track nanochannels of (500±50) nm diameter were used for electrodeposition of Ni nanowires. Using 10⁴ channels per cm², the most favourable deposition potential of  − 1.0 V was determined in a potentiostatic mode by varying the deposition potential with respect to an Ag/AgCl reference electrode over a range between  − 0.1 V and  − 1.5 V. The deposition efficiency at  − 1.0 V was estimated around 10%. The resulting single wires had a resistance around 200 Ω and showed an anisotropic magnetoresistance (AMR) effect of 1%, applicable to directionally sensitive magnetic field sensors.     

聚碳酸酯的热降解

综述了聚碳酸酯的热稳定性及其影响因素,并详细论述了一些添加剂如偶联剂甲基三甲氧基硅烷、钛酸四丁酯、阻燃剂二苯砜磺酸钾(KSS)、聚氨丙基苯基倍半硅氧烷(PAPSQ)等对聚碳酸酯热稳定性的影响,阐述了Kissinger法和Ozawa法等聚合物热降解动力学的分析方法。重点介绍了近期国内外有关聚碳酸酯热降解产物和热降解机理方面的研究成果。     

The properties of equimolar copolycarbonates of bisphenol A with bisphenol S and 1,4-bis(hydroxymethyl)cyclohexane

Ranges of both alternating and random 1:1 copolycarbonates of Bisphenol-A (2,2-bis(4-hydroxyphenyl)propane) and Bisphenol-S (4,4′-dihydroxydiphenyl sulphone) and of Bisphenol-A and 1,4-dimethanoylcyclohexane have been synthesized in order to test the hypothesis that, other things being equal, a more random structured polymer should exhibit superior thermal ageing characteristics. Studies on these materials' mechanical and thermal properties establish that within each pair they are extremely similar and hence the original hypothesis is disproved.     

Dynamic mechanical properties of polycarbonate and acrylonitrile–butadiene–styrene copolymer blends

Blends of polycarbonate (PC) and poly(acrylonitrile‐co‐butadiene‐co‐styrene) (ABS) with different compositions are characterized by means of dynamic mechanical measurements. The samples show phase separation. The shift in the temperatures of the main dynamic mechanical relaxation shown by the blend with respect to those of the pure components is attributed to the migration of oligomers present in the ABS toward the PC in the melt blending process. A comparison with other techniques (dielectric and calorimetric analysis) and the application of the Takayanagi three block model confirm this hypothesis. In all the studied blend compositions (ABS weight up to 28.6%) the PC appears as the matrix where a disperse phase of ABS is present. The scanning and transmission electron microscopy micrographs show that the size of the ABS particles increases when the proportion of ABS in the blend increases. The FTIR results indicate that the interaction between both components are nonpolar in nature and can be enhanced by the preparation procedure. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1507–1516, 2002