The Open Macromolecules Journal最新文献

{"title":"Structure and Rheological Behaviour of Agar Extracted From Madagascar Sea Coast Algae","authors":"Marie Pascaline Rahelivao, H. Andriamanantoanina, A. Heyraud, M. Rinaudo","doi":"10.2174/1874343901407010001","DOIUrl":"https://doi.org/10.2174/1874343901407010001","url":null,"abstract":"Polysaccharide from an original red algae (Gelidium sp) was extracted with hot water, clarified, and precipitat- ed in presence of ethanol. NMR spectroscopic analyses and chromatographic separation after complete hydrolysis showed that this polysaccharide was composed predominantly of a repeating-unit based on 4-O-3,6-anhydro-α-L-galactopyranose and 3-O-β-D-galactopyranose confirming their agar nature. The Gelidium sp agar (representing 16 w % on the basis of dried crude algae) has a regular chemical structure and forms strong gels in aqueous medium. Its rheological behavior is examined as a function of polymer concentration and temperature.","PeriodicalId":22718,"journal":{"name":"The Open Macromolecules Journal","volume":"13 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2014-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75899244","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":"Epoxy Nanocomposites Based on Silylated Montmorillonite: Effect of the Coupling Agents Structure on the Mechanical Properties","authors":"E. Amendola, A. M. Scamardella, G. Callegaro, M. Lavorgna, F. Piscitelli, V. Romeo","doi":"10.2174/1874343901206010033","DOIUrl":"https://doi.org/10.2174/1874343901206010033","url":null,"abstract":"MMT clay-based polymer nanocomposites have been widely studied because of their low cost and unique characteristics, as well as their applications in commercial sectors. The aim of this work was to evaluate the effect of MMT silylated by 3-aminopropyltriethoxysilane and N-(2-aminoethyl)-3-aminopropyltrimethoxysilane on the mechanical behaviour of MMT/epoxy nanocomposites by evaluation of dynamical mechanical analysis and nanoindentation tech- nique. The silicate clay layers were dispersed in the epoxy matrix by sonication process obtaining the intercalation of the epoxy resin inside the inorganic galleries of MMT. The results showed that the MMT modified with N-(2-aminoethyl)-3- aminopropyltrimethoxysilane, which is characterized by the longer alkyl functional group, exhibits an higher compatibil- ity with polymer matrix and improved mechanical properties.","PeriodicalId":22718,"journal":{"name":"The Open Macromolecules Journal","volume":"132 1","pages":"33-36"},"PeriodicalIF":0.0,"publicationDate":"2012-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85732372","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":"Synthesis and Characterization of Methyl Methacrylate Modified Vinylester Resin-Clay Nanocomposites","authors":"Mohamed A. Abdelwahab","doi":"10.2174/1874343901206010020","DOIUrl":"https://doi.org/10.2174/1874343901206010020","url":null,"abstract":"The hybridization of vinylester resin (VER) and organoclay has been studied aiming at enhancing the thermal and mechanical properties of VER. VER prepolymer was synthesized from the reaction of diglycidylether of bisphenol-A and acrylic acid. VER resin-clay nanocomposites were prepared by mixing different ratio of methylmethacrylate (MMA) as a reactive diluent and vinyl functional-montmorillonite with VER. The polymerization of VER in the presence of organoclay has been studied by DSC and IR. The morphology of the hybrids has been studied by XRD. The transparency of the hybrids in the form of films studied by UV-VIS spectra indicated that the transparency depends on the organoclay content. The inclusion of clay into VER led to enhance the hardness, however, with increasing the amount of reactive diluent, the surface hardness decreased. Softening point and TGA studies of the hybrids have also been evaluated.","PeriodicalId":22718,"journal":{"name":"The Open Macromolecules Journal","volume":"24 1","pages":"20-27"},"PeriodicalIF":0.0,"publicationDate":"2012-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84478645","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":"Interfacial Effects in Montmorillonite Filled Polyester Thin Films","authors":"L. Sahu, N. D'Souza","doi":"10.2174/1874343901206010032","DOIUrl":"https://doi.org/10.2174/1874343901206010032","url":null,"abstract":"The behavior of thin supported and non-supported films has been shown to be distinct from the bulk polymer. Separately, high surface area fillers such as montomorillonite layered silicates (MLS) result in improved properties. In this study, we investigate thin films of polyethylene terephthalate (PET) with MLS. The thermal expansivity and glass transi- tion temperature (T g ) were determined using ellipsometry. The results show that with increasing MLS concentration, the glass transition drops for the thin and thick film plateaus. For intermediate thicknesses, a modest influence of the MLS polymer interface on the characteristic length is found. The liquid layer thickness decreases with increased MLS presence. approximately 60 nm. From the experimental results they observed the significant reduction in deviation in T g and CTE of thin film from bulk film as the alkyl chain length was increased from methyl to n-octyl. They attributed to increase in the cooperative segmental length with the addi- tion of solvent. Utilizing a combination of polymer physics (molecular mobility) and polymer miscibility (interactions), Pham and Green (10) explain the contradictory T g -thickness results via a three layer model. Next to a substrate, the poly- mer chains bend and fold over leading to higher density, decreased mobility and higher glass transition temperatures. At the free surface, lower density, higher mobility and lower glass transitions are to be expected. The higher mobility re- sults from an increase in relaxation time due to entropic ef- fects such as disentanglements, confinement effects or by chain-end segregation. Between the free surface and the re- gion close to the substrate, polymer chains have intermediate mobility. When the substrate-polymer interaction is non in- teracting, the thickness of the substrate layer is lower than when there is a high degree of substrate-polymer interaction. The consequence is that the intermediate region in a non- interacting coating is thicker than in an interacting system. In the former the glass transition increases with increasing film thickness. The free surface mobility dominates leading to decreased T g 's with decreasing film thickness. In a film where positive substrate-polymer interactions occur, the glass transition decreases with increasing film thickness as the lower mobility layer dominates.","PeriodicalId":22718,"journal":{"name":"The Open Macromolecules Journal","volume":"6 1","pages":"28-32"},"PeriodicalIF":0.0,"publicationDate":"2012-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81767976","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":"A Dynamic Mechanical and Dielectric Relaxation Study of PP-g-MAH/Clay Nanocomposites","authors":"Amol Ridhore, J. Jog","doi":"10.2174/1874343901206010053","DOIUrl":"https://doi.org/10.2174/1874343901206010053","url":null,"abstract":"The relaxations in maleic anhydride grafted polypropylene (PPgMAH) and its nanocomposite based on organi- cally modified layered silicates were investigated using dynamic mechanical thermal analysis and dielectric relaxation spectroscopy. The results of dynamic mechanical thermal analysis showed that the incorporation of clay in the polymer matrix resulted in two relaxations corresponding to the glass transition and a high temperature transition. In nanocompo- sites, the incorporation of clay resulted in reduction of the loss modulus peak area for the glass transition peak suggesting decreased content of mobile amorphous phase. An increase in the area of the high temperature transition was noted and associated with the presence of rigid amorphous phase. The dielectric measurements indicated presence of a relaxation at high frequency side for the PPgMAH whereas in nanocomposite two relaxations in the low frequency side were observed namely MWS relaxation or the interfacial polarization of the polymer and clay followed by α RAP relaxation due to relaxa- tion of rigid amorphous phase. The presence of rigid amorphous phase was attributed to the strong bonding between the MAH groups of PPgMAH and the clay surface.","PeriodicalId":22718,"journal":{"name":"The Open Macromolecules Journal","volume":"3 1","pages":"53-58"},"PeriodicalIF":0.0,"publicationDate":"2012-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88288599","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":"Mechanical and Gas Barrier Properties of Polypropylene Layered Silicate Nanocomposites: A Review","authors":"V. Mittal","doi":"10.2174/1874343901206010037","DOIUrl":"https://doi.org/10.2174/1874343901206010037","url":null,"abstract":"Polypropylene owing to its apolar nature suffers from compatibility problems with clay, which is partially polar even after the surface modification with alkyl ammonium ions. To circumvent this limitation, polypropylene nanocompo- sites have been synthesized by using two methodologies: a) partial polarization of the matrix by the addition of low mo- lecular weight compatibilizer which owing to its amphiphilic nature acts towards compatibilizing the polymer and inor- ganic phases and b) by completely organophilizing the clay surface by using filler surface modification with long alkyl chains and with higher chain density. The addition of compatibilizer leads to better filler delamination and better me- chanical performance, however, the modulus decreases after a certain extent of compatibilizer owing to plasticization of matrix. The permeation properties were observed to be affected negatively owing to mismatch of the polar compatibilizer chains with apolar surface modification chains. The second methodology, on the other hand, leads to simultaneous im- provement of mechanical and gas barrier properties. Better organophilization of the filler surface reduces the attractive forces between the platelets further and increases their potential of exfoliation in the polymer matrix. Other advanced sur- face modifications dealing with chemical reactions on the surface of the filler have also been reported to increase the basal plane spacing.","PeriodicalId":22718,"journal":{"name":"The Open Macromolecules Journal","volume":"2014 1","pages":"37-52"},"PeriodicalIF":0.0,"publicationDate":"2012-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86683376","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":"Editorial - Recent Developments in Polymer/Clay Composites","authors":"F. Alsewailem","doi":"10.2174/1874343901206010019","DOIUrl":"https://doi.org/10.2174/1874343901206010019","url":null,"abstract":"","PeriodicalId":22718,"journal":{"name":"The Open Macromolecules Journal","volume":"12 1","pages":"19-19"},"PeriodicalIF":0.0,"publicationDate":"2012-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86740556","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":"Monte-Carlo Simulation of Compatibilization by Network-Building and Catalytic Interface Reactions in Two-Component Injection Molding","authors":"A. John, J. Nagel, G. Heinrich","doi":"10.2174/1874343901206010001","DOIUrl":"https://doi.org/10.2174/1874343901206010001","url":null,"abstract":"Adhesion of immiscible polymers during two-component injection molding can be improved by transreactions of properly functionalized molecules in situ by exploitation of the thermal energy of the melts. These reactions must pro- vide a sufficient conversion of reactive monomers in the short cooling time down to the glass temperature. Furthermore, as much as possible interconnecting chemical links on the molecular level have to be created between the components within the small spatial region of the interdiffusion interface width. To investigate these processes, we performed Monte- Carlo (MC) simulations based on the three-dimensional coarse-grained Bond Fluctuation Model (BFM) including a ther- mal interaction potential in r 6 with energy = 0.1 kBT . We compared a simple Split type reaction, which is capable of network-forming, with a catalytic interface reactive process both exhibiting different values of activation energy. The main process of the catalytic reaction system is identical to the simple Split reaction as described in a previous paper, but now a reactive monomer creating process is prefixed. For the reacting systems different physical properties like consump- tion, radius of gyration, concentration profiles or the distribution of the degree of polymerization were calculated as a function of time. Additionally, several functions for the description of the adhesive strength on the molecular level were adopted and calculated depending on reaction type, activation energy and degree of consumption, respectively. From the results, those chemical reaction types were deduced, which should be most suitable for compatibilization intentions in two-component injection molding.","PeriodicalId":22718,"journal":{"name":"The Open Macromolecules Journal","volume":"23 1","pages":"1-18"},"PeriodicalIF":0.0,"publicationDate":"2012-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74748348","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":"Rheological Investigation of the Influence of Short Chain Branching and Mw of LDPE on the Melt Miscibility of LDPE/PP Blends","authors":"I. Hussein, M. Williams","doi":"10.2174/1874343901105010013","DOIUrl":"https://doi.org/10.2174/1874343901105010013","url":null,"abstract":"The influences of short chain branching (SCB) and molecular weight (Mw) of low density polyethylene (LDPE) on its melt miscibility with polypropylene (PP) were investigated by rheological techniques. Rheological meas- urement and different data-treatment techniques as well as rheological models suggest that blends of PP with LDPE of high SCB (22 CH3/1000 C) are miscible at all compositions. However, blends of LDPE with low SCB (8.3 CH3/1000 C) are immiscible in the LDPE-rich and miscible in PP-rich regimes. It was suggested that matching the conformations of PP and LDPE and matching the Mw of LDPE and PP is a key to the melt miscibility of PP/LDPE blends. The experimental results are in agreement with theoretical predictions on the miscibility of polyolefin blends.","PeriodicalId":22718,"journal":{"name":"The Open Macromolecules Journal","volume":"71 1","pages":"13-19"},"PeriodicalIF":0.0,"publicationDate":"2011-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90145493","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":"Compatibilization in Two-Component Injection Molding by Means of SplitReactions with Varying Reactive Sites – a Monte-Carlo Simulation","authors":"A. John, J. Nagel, G. Heinrich","doi":"10.2174/1874343901105010001","DOIUrl":"https://doi.org/10.2174/1874343901105010001","url":null,"abstract":"Adhesion of immiscible polymers during two-component injection molding may be improved by transreactions of properly functionalized molecules in situ using the thermal energy of the melts. These reactions must provide a suffi- cient conversion of reactive monomers during the short cooling time down to the glass temperature and within the small spatial region of the interface width to create as much as possible interconnecting chemical links between the components on the molecular level. To investigate these processes, we performed Monte-Carlo (MC) simulations based on the three dimensional coarse-grained Bond Fluctuation Model (BFM) in a two-phase system. We studied split type reactions exhib- iting reactive monomers at different sites (End, Middle, Random) of the polymers governed by activation energies of EA = 0, 1, 3, 5 and 7 T k B. For the reacting systems several physical properties like consumption, radius of gyration, concentra- tion profiles or the distribution of the degree of polymerization were calculated as a function of time. Additionally, differ- ent functions for the description of adhesion on the molecular level were adopted and calculated depending on reaction type, activation energy and degree of consumption. From the results those chemical reaction types were deduced, which should be most suitable for the compatibilization in two-component injection molding.","PeriodicalId":22718,"journal":{"name":"The Open Macromolecules Journal","volume":"83 1","pages":"1-12"},"PeriodicalIF":0.0,"publicationDate":"2011-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84029536","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}