Funding information Generalitat de Catalunya, Grant/Award Number: 2017SGR373; Spanish Ministry of Economy and Competitiveness, Grant/Award Number: RTI2018-101827-B-I00 Abstract Aliphatic polyamides (nylons) constitute a family of polymers with outstanding properties and multiple applications. Despite the intensive research studies carried out with nylons, there are still multiple unsolved questions concerning crystallization processes, crystalline structures, polymorphic transitions, and crystalline morphologies. Constrains imposed by the strong intermolecular interactions affect the amorphous state, the rigid amorphous phase, the molecular folding, the morphology and obviously the crystalline structure. Some of these relevant points are discussed in the present work.
{"title":"Aliphatic polyamides (nylons): Interplay between hydrogen bonds and crystalline structures, polymorphic transitions and crystallization","authors":"J. Puiggalí","doi":"10.1002/pcr2.10199","DOIUrl":"https://doi.org/10.1002/pcr2.10199","url":null,"abstract":"Funding information Generalitat de Catalunya, Grant/Award Number: 2017SGR373; Spanish Ministry of Economy and Competitiveness, Grant/Award Number: RTI2018-101827-B-I00 Abstract Aliphatic polyamides (nylons) constitute a family of polymers with outstanding properties and multiple applications. Despite the intensive research studies carried out with nylons, there are still multiple unsolved questions concerning crystallization processes, crystalline structures, polymorphic transitions, and crystalline morphologies. Constrains imposed by the strong intermolecular interactions affect the amorphous state, the rigid amorphous phase, the molecular folding, the morphology and obviously the crystalline structure. Some of these relevant points are discussed in the present work.","PeriodicalId":36413,"journal":{"name":"Polymer Crystallization","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2021-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/pcr2.10199","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44663851","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}
Shohei Iwasaki, Mitsuko Inoue, Yurie Takei, R. Nishikawa, M. Yamaguchi
{"title":"Modulus enhancement of polypropylene by sorbitol nucleating agent in flow field","authors":"Shohei Iwasaki, Mitsuko Inoue, Yurie Takei, R. Nishikawa, M. Yamaguchi","doi":"10.1002/pcr2.10170","DOIUrl":"https://doi.org/10.1002/pcr2.10170","url":null,"abstract":"","PeriodicalId":36413,"journal":{"name":"Polymer Crystallization","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2021-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/pcr2.10170","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44015154","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}
{"title":"Cross hatched structure of polyethylene spherulites","authors":"S. Yakovlev, K. Downing, P. Brant","doi":"10.1002/PCR2.10174","DOIUrl":"https://doi.org/10.1002/PCR2.10174","url":null,"abstract":"","PeriodicalId":36413,"journal":{"name":"Polymer Crystallization","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2021-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/PCR2.10174","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48718687","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}
Funding information National Natural Science Foundation of China, Grant/Award Numbers: 21873054, 21861132018, U1862205; National Science and Technology Major Project, Grant/Award Number: 2017YFB0309301; Tsinghua University Scientific Research Project, Grant/ Award Number: 20194180048 Abstract Secondary nucleation on the surfaces of growing crystals plays a vital role in polymer crystallization, which determines the lamellar thickness at growth front and the radial growth rate. Though secondary nucleation has been intensively studied in the past decades, our understanding on the molecular mechanism and kinetics is not yet complete. In this perspective, we will briefly review the major advances in the secondary nucleation of flexible polymer chains in the past decade and discuss some remained questions from a viewpoint of kinetics. The main theories, thermodynamics and kinetics of secondary nucleation are first summarized. The difference of nucleation of polymer chains from that of small molecular crystals is revealed via analysis of kinetics. Then, the interplay of various microscopic processes leading to the final crystalline structures is discussed, such as lamellar thickening versus widening, intra-chain vs inter-chain nucleation, secondary nucleation versus lateral spreading, secondary vs primary nucleation, nucleation of polymorphisms, and so forth. Finally, some remained open questions are highlighted. Combining kinetic theory considering various microscopic processes and new experimental evidences at different length and time scales would greatly help deepen our understanding on the secondary nucleation during crystallization of flexible polymer chains.
{"title":"Secondary nucleation in polymer crystallization: A kinetic view","authors":"Shujing Zhang, Zhiqi Wang, Baohua Guo, Jun Xu","doi":"10.1002/PCR2.10173","DOIUrl":"https://doi.org/10.1002/PCR2.10173","url":null,"abstract":"Funding information National Natural Science Foundation of China, Grant/Award Numbers: 21873054, 21861132018, U1862205; National Science and Technology Major Project, Grant/Award Number: 2017YFB0309301; Tsinghua University Scientific Research Project, Grant/ Award Number: 20194180048 Abstract Secondary nucleation on the surfaces of growing crystals plays a vital role in polymer crystallization, which determines the lamellar thickness at growth front and the radial growth rate. Though secondary nucleation has been intensively studied in the past decades, our understanding on the molecular mechanism and kinetics is not yet complete. In this perspective, we will briefly review the major advances in the secondary nucleation of flexible polymer chains in the past decade and discuss some remained questions from a viewpoint of kinetics. The main theories, thermodynamics and kinetics of secondary nucleation are first summarized. The difference of nucleation of polymer chains from that of small molecular crystals is revealed via analysis of kinetics. Then, the interplay of various microscopic processes leading to the final crystalline structures is discussed, such as lamellar thickening versus widening, intra-chain vs inter-chain nucleation, secondary nucleation versus lateral spreading, secondary vs primary nucleation, nucleation of polymorphisms, and so forth. Finally, some remained open questions are highlighted. Combining kinetic theory considering various microscopic processes and new experimental evidences at different length and time scales would greatly help deepen our understanding on the secondary nucleation during crystallization of flexible polymer chains.","PeriodicalId":36413,"journal":{"name":"Polymer Crystallization","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2021-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/PCR2.10173","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41249221","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}
The rheology of polymer crystallization is an old problem that often defies explanation due to the complex interrelationships between crystallization and flow properties. Although separate measurements of rheology and crystallinity can give some information on their relationship, it is only through simultaneous measurements that ideas on the rheology of polymer crystallization can be tested and developed. This Perspective details recent experimental developments in simultaneous crystallinity and rheology measurements as well as continuum modeling efforts for the case of quiescent and isothermal crystallization. Experimental results reveal that the rheology is dominated initially by growth of individual spherulites that evolve into spherulitic superstructures that eventually span the measurement geometry. A generalized effective medium model based on this concept of percolation can explain both the growth of the viscoelastic modulus during crystallization and the changes in the relaxation spectrum of the crystallizing polymer, including a critical gel response at percolation. The success of the combined measurement techniques and percolation concepts motivate research to extend the semicrystalline polymer materials space where these methods are applied as well as further develop novel techniques to gain additional insight into the evolution of structure and relaxation dynamics during crystallization.
{"title":"Percolation Implications in the Rheology of Polymer Crystallization.","authors":"Anthony P Kotula, Kalman B Migler","doi":"10.1002/pcr2.10162","DOIUrl":"10.1002/pcr2.10162","url":null,"abstract":"<p><p>The rheology of polymer crystallization is an old problem that often defies explanation due to the complex interrelationships between crystallization and flow properties. Although separate measurements of rheology and crystallinity can give some information on their relationship, it is only through simultaneous measurements that ideas on the rheology of polymer crystallization can be tested and developed. This Perspective details recent experimental developments in simultaneous crystallinity and rheology measurements as well as continuum modeling efforts for the case of quiescent and isothermal crystallization. Experimental results reveal that the rheology is dominated initially by growth of individual spherulites that evolve into spherulitic superstructures that eventually span the measurement geometry. A generalized effective medium model based on this concept of percolation can explain both the growth of the viscoelastic modulus during crystallization and the changes in the relaxation spectrum of the crystallizing polymer, including a critical gel response at percolation. The success of the combined measurement techniques and percolation concepts motivate research to extend the semicrystalline polymer materials space where these methods are applied as well as further develop novel techniques to gain additional insight into the evolution of structure and relaxation dynamics during crystallization.</p>","PeriodicalId":36413,"journal":{"name":"Polymer Crystallization","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8193685/pdf/nihms-1700005.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39110385","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Crystallization behavior of poly(lactic acid) and its blends","authors":"Yaming Wang, Chuntai Liu, Changyu Shen","doi":"10.1002/pcr2.10171","DOIUrl":"https://doi.org/10.1002/pcr2.10171","url":null,"abstract":"","PeriodicalId":36413,"journal":{"name":"Polymer Crystallization","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2020-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/pcr2.10171","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43931618","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}
S. Boyer, J. Haudin, Vivian Song, Vincent Bourassier, P. Navard, C. Barron
The improvement of cellulosic biomass-polymer composites needs to evaluate what occurs at the biomass-matrix interface during crystallization. Different well-defined maize tissues were obtained by original dry fractionation processes, without chemical treatment. Their morphological features were identified by optical and scanning electron microscopies. For each type of tissue, a small fragment was sandwiched between two films of isotactic polypropylene. The composite was subjected to quiescent isothermal conditions, followed in-situ by polarized optical microscopy. Focus of the heterogeneous nucleation at the surface of maize tissues showed that in all cases, more or less numerous semi-crystalline entities originated from the tissue surface, indicating a moderate nucleating activity. Different crystallization behaviors were observed as a function of the tissue. Growth rates of surface layers were generally higher that the growth rates of bulk spherulites. The differences were small, but significant. They were discussed within the frame of kinetic theory of growth.
{"title":"Transcrystallinity in maize tissues/polypropylene composites: First focus of the heterogeneous nucleation and growth stages versus tissue type","authors":"S. Boyer, J. Haudin, Vivian Song, Vincent Bourassier, P. Navard, C. Barron","doi":"10.1002/PCR2.10155","DOIUrl":"https://doi.org/10.1002/PCR2.10155","url":null,"abstract":"The improvement of cellulosic biomass-polymer composites needs to evaluate what occurs at the biomass-matrix interface during crystallization. Different well-defined maize tissues were obtained by original dry fractionation processes, without chemical treatment. Their morphological features were identified by optical and scanning electron microscopies. For each type of tissue, a small fragment was sandwiched between two films of isotactic polypropylene. The composite was subjected to quiescent isothermal conditions, followed in-situ by polarized optical microscopy. Focus of the heterogeneous nucleation at the surface of maize tissues showed that in all cases, more or less numerous semi-crystalline entities originated from the tissue surface, indicating a moderate nucleating activity. Different crystallization behaviors were observed as a function of the tissue. Growth rates of surface layers were generally higher that the growth rates of bulk spherulites. The differences were small, but significant. They were discussed within the frame of kinetic theory of growth.","PeriodicalId":36413,"journal":{"name":"Polymer Crystallization","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2020-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/PCR2.10155","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44355073","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}
A. Menyhárd, J. Molnár, Zsuzsanna Horváth, F. Horváth, D. Cavallo, P. Polyák
This work demonstrates and models the self-organization of mixed polymorps in polymers containing simultaneously growing phases with different growth rates. The model was verified and demonstrated in isotactic polypropylene nucleated by a non-selective nucleating agent. The crystallization and melting processes were studied by calorimetry (DSC) and polarized light microscopy (PLM). The morphology of the samples was investigated using PLM and scanning electron microscopy (SEM). The funda-mental rules of the formation of two polymorphic modifications developing simultaneously on the same nucleating particle are introduced. A simple equation is suggested to predict the morphological geometry on the lateral surface of the nucleating agent. The results indicated good agreement between the predicted and observed geometry. The proposed model explains the self-organization of micro-sized reinforcements of α -modification in the matrix of β -iPP. Although the proposed equation was tested for this particular case it is a general equation for all structures in which different polymorphs are growing simultaneously with different growth rates.
{"title":"Self‐organization of micro reinforcements and the rules of crystal formation in polypropylene nucleated by non‐selective nucleating agents with dual nucleating ability","authors":"A. Menyhárd, J. Molnár, Zsuzsanna Horváth, F. Horváth, D. Cavallo, P. Polyák","doi":"10.1002/pcr2.10136","DOIUrl":"https://doi.org/10.1002/pcr2.10136","url":null,"abstract":"This work demonstrates and models the self-organization of mixed polymorps in polymers containing simultaneously growing phases with different growth rates. The model was verified and demonstrated in isotactic polypropylene nucleated by a non-selective nucleating agent. The crystallization and melting processes were studied by calorimetry (DSC) and polarized light microscopy (PLM). The morphology of the samples was investigated using PLM and scanning electron microscopy (SEM). The funda-mental rules of the formation of two polymorphic modifications developing simultaneously on the same nucleating particle are introduced. A simple equation is suggested to predict the morphological geometry on the lateral surface of the nucleating agent. The results indicated good agreement between the predicted and observed geometry. The proposed model explains the self-organization of micro-sized reinforcements of α -modification in the matrix of β -iPP. Although the proposed equation was tested for this particular case it is a general equation for all structures in which different polymorphs are growing simultaneously with different growth rates.","PeriodicalId":36413,"journal":{"name":"Polymer Crystallization","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2020-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/pcr2.10136","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48943710","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}
W. Qin, Kehua Liu, Z. Xin, H. Ling, Shuai Zhou, Shicheng Zhao
{"title":"Zinc pimelate as an effective β‐nucleating agent for isotactic polypropylene at elevated pressures and under rapid cooling rates","authors":"W. Qin, Kehua Liu, Z. Xin, H. Ling, Shuai Zhou, Shicheng Zhao","doi":"10.1002/pcr2.10132","DOIUrl":"https://doi.org/10.1002/pcr2.10132","url":null,"abstract":"","PeriodicalId":36413,"journal":{"name":"Polymer Crystallization","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/pcr2.10132","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41436670","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}
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