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IPN foams IPN泡沫
Journal of Polymer Science: Polymer Symposia Pub Date : 1985-01-01 DOI: 10.1002/polc.5070720128
Kurt C. Frisch, Dilip Sakhpara, Harry L. Frisch
{"title":"IPN foams","authors":"Kurt C. Frisch,&nbsp;Dilip Sakhpara,&nbsp;Harry L. Frisch","doi":"10.1002/polc.5070720128","DOIUrl":"https://doi.org/10.1002/polc.5070720128","url":null,"abstract":"<p>Semirigid IPN foams were prepared by simultaneous polymerization (SIN technique) of urethane-isocyanurate and epoxy resin systems. Significantly higher compressive strength was obtained with the IPN foams as compared to the corresponding urethane-isocyanurate foams. Due to the relatively low functionality of the foam components, and hence, resulting low crosslink density of the IPN foams, the oxygen indices and the friability were relatively low but increased with increasing isocyanate index and epoxy content. Although these studies were preliminary in nature, this type of IPN foams could find applications in sound and noise attenuation as well as for energy absorption such as shock and vibration damping.</p>","PeriodicalId":16867,"journal":{"name":"Journal of Polymer Science: Polymer Symposia","volume":"72 1","pages":"277-293"},"PeriodicalIF":0.0,"publicationDate":"1985-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/polc.5070720128","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138079202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Molecular degradation of polymers 聚合物的分子降解
Journal of Polymer Science: Polymer Symposia Pub Date : 1985-01-01 DOI: 10.1002/polc.5070720117
K. L. Devries, M. Igarashi, F. Chao
{"title":"Molecular degradation of polymers","authors":"K. L. Devries,&nbsp;M. Igarashi,&nbsp;F. Chao","doi":"10.1002/polc.5070720117","DOIUrl":"10.1002/polc.5070720117","url":null,"abstract":"<p>An understanding of the transmittal of force or stress through the molecular (or atomic) network of a body should not only be helpful in predicting the load carrying capability of materials but might also provide information on how structure can be altered to enhance properties. A molecular understanding of mechanical properties is particularly difficult in polymers where such factors as molecular weight, tacticity, crystallinity, presence of networks, orientation, etc., may have an influence. In no class of materials are intricacies of physical structure more important than in polymers. Polymers with very similar chemical structures but differing physical structure can have physical properties differing by orders of magnitude. It would obviously be helpful to have means to probe molecular and atomic events and occur during the loading and destruction of the polymer structure. Instruments that have been used for this purpose include: (1) electron spin resonance (ESR) to monitor free radical production resulting from homolytic chain scission, (2) Fourier transform infrared spectroscopy (FTIR) to measure new end groups resulting from molecular chain rupture, and (3) intrinsic viscosity or gel permeation chromotography (GPC) to detect molecular weight changes (MWC) accompanying molecular degradation. This presentation will discuss and compare research results from these methods. Particular emphasis will be placed on recent studies in which computer modeling has been used to identify ESR spectra and a comparison of the results obtained by ESR, FTIR, and MWC for polystyrene.</p>","PeriodicalId":16867,"journal":{"name":"Journal of Polymer Science: Polymer Symposia","volume":"72 1","pages":"111-129"},"PeriodicalIF":0.0,"publicationDate":"1985-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/polc.5070720117","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86153366","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 2
Some evidence for the existence of the liquid-liquid transition: Melt rheology studies 液-液过渡存在的一些证据:熔体流变学研究
Journal of Polymer Science: Polymer Symposia Pub Date : 1985-01-01 DOI: 10.1002/polc.5070720137
Bryce Maxwell, Kevin S. Cook
{"title":"Some evidence for the existence of the liquid-liquid transition: Melt rheology studies","authors":"Bryce Maxwell,&nbsp;Kevin S. Cook","doi":"10.1002/polc.5070720137","DOIUrl":"10.1002/polc.5070720137","url":null,"abstract":"<p>In 1963 Boyer proposed the existence of a liquid-liquid transition, T<sub>ll</sub>, in polystyrene above the glass transition T<sub>g</sub>. Since that time there has been considerable discussion and disagreement on the existence of this transition. Detailed shear modulus data as a function of temperature in the range 165–215°C will be presented for a series of polystyrenes of various molecular weights. In each case, as the temperature is increased, the modulus gradually decreases until a specific molecular weight dependent temperature is reached and then suddenly the modulus decreases rapidly over a few °C and then returns to its previous gradual decrease with increasing temperature. The response is reminiscent of the modulus behavior going through T<sub>g</sub>. It is suggested that the temperature at which this sharp decreased in modulus takes place is T<sub>ll</sub>. The molecular weight effects on T<sub>ll</sub> will be discussed in terms of several rheological properties that measure the temperature of this transition.</p>","PeriodicalId":16867,"journal":{"name":"Journal of Polymer Science: Polymer Symposia","volume":"72 1","pages":"343-350"},"PeriodicalIF":0.0,"publicationDate":"1985-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/polc.5070720137","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88698807","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 3
Structure–property relationships in main chain liquid crystal polyesters with flexible spacers† 带柔性隔层的主链液晶聚酯的结构-性能关系
Journal of Polymer Science: Polymer Symposia Pub Date : 1985-01-01 DOI: 10.1002/polc.5070720103
Robert W. Lenz
{"title":"Structure–property relationships in main chain liquid crystal polyesters with flexible spacers†","authors":"Robert W. Lenz","doi":"10.1002/polc.5070720103","DOIUrl":"10.1002/polc.5070720103","url":null,"abstract":"<p>Investigations have been carried out in this laboratory over the past four years on the structure—property relationship in main chain, thermotropic liquid crystal polymers containing a variety of different types of mesogenic groups and flexible spacers. Our goal has been to relate the effect of polymer structure to the type of mesophase formed in the melt and to the melting and clearing temperatures of the mesophases. Many interesting, unusual, and unexpected results have been obtained in our survey, and this review is concerned with our observations on the molecular factors which determine the types of mesophases formed, nematic or smectic, and their transition temperatures and behaviors.</p>","PeriodicalId":16867,"journal":{"name":"Journal of Polymer Science: Polymer Symposia","volume":"72 1","pages":"1-8"},"PeriodicalIF":0.0,"publicationDate":"1985-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/polc.5070720103","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86356194","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 10
Molecular theory expressions for the stress tensor in flowing polymeric liquids 流动聚合物液体中应力张量的分子理论表达式
Journal of Polymer Science: Polymer Symposia Pub Date : 1985-01-01 DOI: 10.1002/polc.5070730124
R. Byron Bird, C. F. Curtiss
{"title":"Molecular theory expressions for the stress tensor in flowing polymeric liquids","authors":"R. Byron Bird,&nbsp;C. F. Curtiss","doi":"10.1002/polc.5070730124","DOIUrl":"10.1002/polc.5070730124","url":null,"abstract":"<p>Various molecular expressions for the stress tensor for polymeric liquids are given and interrelated. Particular attention is paid to restrictions associated with constraints in the molecular models, hydrodynamic interaction, and molecular confinement in concentrated systems. A recently derived generalization of the Kramers-Kirkwood stress-tensor formula can be taken as the starting point for many polymer calculations.</p>","PeriodicalId":16867,"journal":{"name":"Journal of Polymer Science: Polymer Symposia","volume":"73 1","pages":"187-199"},"PeriodicalIF":0.0,"publicationDate":"1985-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/polc.5070730124","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87294608","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 10
The thinking injection molding machine: A followup to systematic process analyses 思维注塑机:系统工艺分析的后续
Journal of Polymer Science: Polymer Symposia Pub Date : 1985-01-01 DOI: 10.1002/polc.5070720136
G. Menges, W. Janke, A. Matzke
{"title":"The thinking injection molding machine: A followup to systematic process analyses","authors":"G. Menges,&nbsp;W. Janke,&nbsp;A. Matzke","doi":"10.1002/polc.5070720136","DOIUrl":"10.1002/polc.5070720136","url":null,"abstract":"<p>Latest injection molding machines are often equipped with process control computers monitoring and controlling operating sequence, injection speed, holding pressure, clamping motion, clamping force, and all temperatures. This provides for the possibility to overlay process-related optimization programs for adaptation of the machine to the respective material condition and programs for the machine control. The following pages inform about such optimization programs.</p>","PeriodicalId":16867,"journal":{"name":"Journal of Polymer Science: Polymer Symposia","volume":"72 1","pages":"331-341"},"PeriodicalIF":0.0,"publicationDate":"1985-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/polc.5070720136","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"111989569","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
Diffusion and brownian motion of polymeric liquids 聚合物液体的扩散和布朗运动
Journal of Polymer Science: Polymer Symposia Pub Date : 1985-01-01 DOI: 10.1002/polc.5070730123
A. Baumgärtner
{"title":"Diffusion and brownian motion of polymeric liquids","authors":"A. Baumgärtner","doi":"10.1002/polc.5070730123","DOIUrl":"10.1002/polc.5070730123","url":null,"abstract":"<p>The dynamics of dense model systems of pearl-necklace polymer chains, consisting of up to <i>N</i> = 98 hard spheres each, has been investigated using Monte Carlo methods. Excluded volume conditions as well as entanglement constraints have been taken into account. The time-dependent displacement of a single monomer on the chain follows the classic Rouse equation <i>gr(t)</i> α t<sup>1/2</sup> until the monomer equilibrates, whereas the diffusion constant for the center-of-mass motion is in agreement with the reptation law <i>D</i> α <i>N</i><sup>−2±0.2</sup>. The equilibration time for conformational fluctuations is given by the Rouse equation T<sub>e</sub> α <i>N</i><sup>2</sup>, whereas the disengagement time, after which the motion of the monomers is dominated by the center-of-mass motion, is given by <i>T<sub>d</sub></i>, α <i>N</i><sup>3.4±0.2</sup>.</p>","PeriodicalId":16867,"journal":{"name":"Journal of Polymer Science: Polymer Symposia","volume":"73 1","pages":"181-186"},"PeriodicalIF":0.0,"publicationDate":"1985-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/polc.5070730123","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88382325","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
Kinetics of aggregation and gelation 聚集和凝胶动力学
Journal of Polymer Science: Polymer Symposia Pub Date : 1985-01-01 DOI: 10.1002/polc.5070730107
H. Eugene Stanley, Fereydoon Family, Harvey Gould
{"title":"Kinetics of aggregation and gelation","authors":"H. Eugene Stanley,&nbsp;Fereydoon Family,&nbsp;Harvey Gould","doi":"10.1002/polc.5070730107","DOIUrl":"10.1002/polc.5070730107","url":null,"abstract":"<p>We define six kinetic growth models that have witnessed an explosion of recent activity: \u0000 </p><p>We also describe briefly some of the approaches used to study these models, with emphasis on the re normalization group approach being developed by us.</p>","PeriodicalId":16867,"journal":{"name":"Journal of Polymer Science: Polymer Symposia","volume":"73 1","pages":"19-37"},"PeriodicalIF":0.0,"publicationDate":"1985-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/polc.5070730107","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"105404473","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 596
Diffusion in polymer-solvent systems 聚合物溶剂体系中的扩散
Journal of Polymer Science: Polymer Symposia Pub Date : 1985-01-01 DOI: 10.1002/polc.5070720130
J. Larry Duda, James S. Vrentas
{"title":"Diffusion in polymer-solvent systems","authors":"J. Larry Duda,&nbsp;James S. Vrentas","doi":"10.1002/polc.5070720130","DOIUrl":"10.1002/polc.5070720130","url":null,"abstract":"<p>Recent advances in the area of molecular diffusion in polymer-solvent systems will be reviewed. Alfrey's classification scheme for the diffusion of solvent molecules in polymers will be used as a starting point. It will be shown that the various regions on Alfrey's diagram are distinguished by the ratio of two characteristic times, a characteristic relaxation time for the polymer-solvent system and a characteristic diffusion time. Fickian diffusion is realized when this characteristic ratio is a small number, and anomalous behavior occurs when these two characteristic times are the same order of magnitude. Alfrey's “null” region corresponds to those conditions where this dimensionless ratio is much greater than one. The different manifestations of anomalous diffusion with polymer-solvent systems will be discussed, including case II transport as defined by Alfrey, Gurnee, and Lloyd. Finally, diffusion in polymer-solvent systems above the glass transition temperature where classical diffusion theory is applicable will be considered. Emphasis will be placed on the demonstration of the ability of theoretical methods based on free volume concepts to predict the concentration and temperature dependencies of diffusion coefficients. The extension of this free volume theory to describe diffusion in glassy polymers will also be demonstrated. Experimental results for several polymer-solvent systems which exhibit different types of transport behavior will be used to illustrate the correlative and predictive capabilities of these recently developed theories.</p>","PeriodicalId":16867,"journal":{"name":"Journal of Polymer Science: Polymer Symposia","volume":"72 1","pages":"299"},"PeriodicalIF":0.0,"publicationDate":"1985-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/polc.5070720130","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72791533","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 79
Diffusion-limited gelation 凝胶扩散限制
Journal of Polymer Science: Polymer Symposia Pub Date : 1985-01-01 DOI: 10.1002/polc.5070730106
T. A. Witten Jr.
{"title":"Diffusion-limited gelation","authors":"T. A. Witten Jr.","doi":"10.1002/polc.5070730106","DOIUrl":"10.1002/polc.5070730106","url":null,"abstract":"Diffusion-limited aggregation is a means of forming continuous random networks of low density. Recent work on diffusion-limited aggregation is reviewed. These aggregates have universal power-law density correlations. This implies scaling laws relating an aggregate's size to its mass when it is grown from a point, line, or surface. The mass of the growing interface scales as a power of the total mass, but not in the way suggested by simple estimates. A mean field model of the process yields a density that falls inversely as the distance from the origin. It is speculated that the mean field solution may be stable above some spatial dimension dc.","PeriodicalId":16867,"journal":{"name":"Journal of Polymer Science: Polymer Symposia","volume":"73 1","pages":"7-18"},"PeriodicalIF":0.0,"publicationDate":"1985-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/polc.5070730106","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81036069","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
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