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Vincenzo Contaldi Luigi Imperato Silvia Orsi Ernesto Di Maio Paolo Antonio Netti Salvatore Iannace 《应用聚合物科学杂志》2016,133(48)
In this article, we reports the effects of the processing conditions on the morphological and hollow attributes of polystyrene micrometric hollow particles produced by the use of a recently developed technique based on the gas foaming of spherical, dense particles. By modulating the foaming temperature and saturation pressure, we produced hollow particles with different attributes in terms of hollow dimensions, eccentricity, and open–close features. The results from these small systems were compared, and we found agreement with what is typically observed in bulk polymeric foaming, for example, an increase in the foaming efficiency with saturation pressure and the nonmonotonic effect of temperature. Furthermore, we observed an increase in the hollow number when using nucleating agents with respect to the neat polymer and when using nitrogen with respect to carbon dioxide as the blowing agent. The effects of particle manipulation before foaming to achieve hollow elongated or distorted particles are also reported. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44236. 相似文献
964.
Xiaolin Yi Lei Kong Xia Dong Xiaobiao Zuo Xiao Kuang Zhihai Feng Dujin Wang 《Polymer International》2016,65(9):1031-1038
The porous structure evolution of thermosetting phenolic resin controlled by polymerization induced viscoelastic phase separation from solution was investigated in this work. The ultimate morphology and the evolution of a porous texture for the resol resin/solvent system were characterized by digital camera and optical microscopy. In-situ Fourier transform infrared spectroscopy and a rheological method were used to trace the curing reaction of the resol resin/solvent system. The impacts of solvent content and curing temperature on the foaming behavior were quantitatively and systematically investigated. Based on the relationship between the morphology evolution and curing dynamics, the foaming mechanism of the polymerization induced viscoelastic phase separation was elucidated. The present work provides new insight into the foaming mechanism of thermosetting materials and may be helpful for morphological control in the preparation of lightweight porous phenolic material. © 2016 Society of Chemical Industry 相似文献
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国内偶氮二甲酰胺发泡剂生产与应用 总被引:5,自引:0,他引:5
游贤德 《化学推进剂与高分子材料》2004,2(1):44-48
概述肼基发泡剂的种类及性能。着重论述国内偶氮二甲酰胺 (AC)发泡剂的生产发展状况、生产工艺改进、产品应用现状及开发重点。 相似文献
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Effect of matrix−nanoparticle supramolecular interactions on the morphology and mechanical properties of polymer foams 下载免费PDF全文
In this study, we report the fabrication of supramolecular polymer nanocomposite foams with a uniform cell structure, high cell density and high expansion ratio using a soft matrix of poly(methyl acrylate‐co‐2‐hydroxyethyl methacrylate) and silica nanoparticle fillers, both functionalized with ureido‐pyrimidinone (UPy) supramolecular groups. Microcellular structures were formed using a batch foaming process at 90 °C under a 9 MPa nitrogen atmosphere. Nanocomposites were characterized and compared before and after the foaming process to investigate the effect of supramolecular interactions on the thermomechanical properties and morphology of the foams. TEM images revealed that while strong inter‐filler supramolecular interactions do not have a positive effect on their dispersion state, matrix?filler interactions derived from hydrogen bonding UPy motifs result in a rather uniform distribution of nanoparticles. Competing filler?filler and matrix?filler supramolecular interactions can be balanced and optimized by adjusting UPy populations along the chains and on the surface of nanoparticles. At a given chain functionality, increasing the nanoparticle loading up to an optimum concentration improves the mechanical properties and formability of the system. Above such concentration strong interactions between fillers, which are not compensated by the matrix, result in large aggregates and consequently undermine the material performance. Supramolecular polymer foams illustrate a similar thermal and viscoelastic behavior to that of neat samples but after foaming, due to the formation of a cellular structure and rearrangement or dissociation of UPy dimers under the foaming conditions, the elastic modulus is reduced. © 2018 Society of Chemical Industry 相似文献
969.
Novel poly(aryl ether nitrile ketone) foams and the influence of copolymer structure on the foaming result 下载免费PDF全文
Novel poly(aryl ether nitrile ketone) foams were prepared through the batch foaming method with supercritical CO2 as the blowing agent. Both temperature‐induced and pressure‐induced foaming methods were conducted to examine the influence of nitrile groups on the foaming result. The results indicated that nitrile groups influenced the foaming result by affecting both the viscoelasticity and CO2 absorption of the polymers. In addition, the CO2 solubility of the polymers increased with increasing CN content presumably because of the Lewis acid–base nature of the interaction between the CO2 molecules and the nitrile groups. The cell growth process was assessed by analyzing the influence of foaming temperature and foaming time on the cell morphology. Nanocellular foams with a minimum size of 30–50 nm were achieved by the temperature‐induced foaming method. Moreover, highly expanded foams with a maximum expansion ratio of 23.6 were obtained by the pressure‐induced foaming method. © 2018 Society of Chemical Industry 相似文献
970.
卓越工程师教育培养计划旨在造就一大批创新能力强、适应经济社会发展需要的高质量工程技术人才。本文针对计科专业《工程识图》课程的教学方法展开研究,提出基于思维训练和能力培养的教学目标,以期为我校卓越工程师试点专业的课程改革提供新的思路。 相似文献