In this research work poly(vinyl chloride)(PVC), ethylene vinyl acetate copolymer (EVA), and Maghnite nanoclay (MGT) were used to prepare PVC/EVA nanocomposites. The MGT clay was intercalated with octadecyltrimethylammonium chloride (ODTMA) and grafted with γ-aminopropyltriethoxysilane (APTES). The blend nanocomposites were prepared through the melt mixing of PVC/EVA blend at a weight ratio of 50/50 (wt%/wt%) with 20 wt% of compatibilizer; ethylene vinyl acetate grafted with an alcohol (EVA-g-OH) and 3 wt% of modified MGT clay using a Brabender plastograph. The nanocomposites so prepared were characterized using X-ray diffraction, TGA/DTA, mechanical tests and SEM. The results showed that when PVC was blended with EVA, with the modified MGT and with the compatibilizer, synergistic effects in the thermal stability and mechanical properties were observed.

Nanocomposites based on poly(vinylidene fluoride) (PVDF)/poly(methyl methacrylate) (PMMA) with untreated clay were prepared in one step by reactive melt extrusion. Chemical reactions took place between the polymer matrices, the inorganic clay particles, and three reactive agents, leading to the PVDF/PMMA/clay nanocomposites. The microstructure characterizations were carried out by differential scanning calorimetry and wide-angle X-ray scattering (WAXS). The mechanical behavior was investigated by tensile experiments, impact tests, and microhardness measurements. The morphological characterization was carried out by optical and atomic force microscopy (AFM). The decrease of the melting and crystallization temperatures of the PVDF with the increasing PMMA content is attributed to the interactions between the oxygen of the PMMA carbonyl group and the PVDF’s hydrogen atom. WAXS analysis shows that there is neither an intercalation step nor total exfoliation in any composition. As the PMMA content increases, WAXS diagrams show either the PVDF α -crystallographic form, both, α - and β -forms, or only the β -form. For PMMA contents higher than 40 wt%, the materials became amorphous. The microhardness of the samples decrease for a PMMA content up to 20 wt%. The study by optical microscopy and AFM illustrates the significant effect in the presence of clay on the film’s surface morphology.

The first example of synergistic alkynyl-tin initiated ring-opening polymerization of cyclic ester in the presence of nanotubular silica particles is herein reported. Hydroxyl groups on the halloysite (HNTs) surface act as initiators for caprolactone polymerization and the resulting polymers are covalently grafted to the HNTs. The covalent anchorage of the poly(epsilon-caprolactone) (PCL) backbone to the HNTs ensures a high degree of interpenetration at the hybrid interface thereby allowing long-term stability of the PCL-grafted-HNTs suspension. Scanning electron microscopy analyses showed the uniform dispersion of the HNTs filler within the PCL matrix. The melt viscosity of the poly(epsilon-caprolactone)/HNTs composites decreases with increasing clay content. Thermal stability and microindentation hardness properties of the resulting nano-composites were significantly improved, as compared to native, non-reinforced PCL. (C) 2016 Elsevier Ltd. All rights reserved.

Blends of isotactic polypropylene (iPP) and polycarbonate (PC) with and without a compatibilizer were prepared using a Brabender Haake Rheocord at 260 degrees C and 32 rpm. Maleic anhydride grafted styrene-ethylene/butylene-styrene (SEBS-g-MAH) and maleic anhydride grafted ethylene-propylene diene (EPDM-g-MAH) were chosen as compatibilizers and their proportion was set to 5, 10, and 15 wt%, respectively. The thermal properties and crystallization behavior were determined by differential scanning calorimetry (DSC) and wide angle X-ray scattering (WAXS). Micromechanical properties were also investigated using a Vickers microindentation tester. The DSC analysis indicates that the melting temperature of iPP in the all the blends, compatibilized and uncompatibilized ones, remains constant and is almost the same as those of the pure component. On the other hand, it is shown that the degree of crystallinity of iPP in the blends calculated by DSC and WAXS is dependent of the composition of the polymeric mixture. However the hardness (H) decreases with increasing PC content until the composition of iPP/PC (75/25) is reached, whereas for larger PC content values, H increases. The same trend was obtained with the addition of both compatibilizers. POLYM. ENG. SCI., 56:1138-1145, 2016. (c) 2016 Society of Plastics Engineers

Abstract Poly (vinylidene fluoride) (PVDF)-untreated clay nanocomposites were successfully prepared using an innovative one-step reactive melt extrusion process. Through specific temperature and shear conditions, the chemical reactions took place between the polymer matrix, the inorganic clay particles, and three main reactive agents: an organic peroxide, sulfur, and a specific activator led finally to the PVDF-clay nanocomposites. The materials were formulated with various amounts of clay in order to identify the best conditions, enabling to obtain the optimal particle exfoliation in the polymer matrix at the nanometric scale. The microstructure and nanostructure modifications were characterized by Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), and wide- and small-angle X-ray scattering (WAXS and SAXS). The relationship between nanostructure and mechanical behavior was investigated by tensile experiments, impact tests, and microhardness measurements. The FTIR results suggest that there is a chemical interaction between the clay and the polymer. Furthermore, the WAXS study shows that no intercalation step takes place in any composition. In addition to this, the sample with 2.5 wt.% clay could present a total exfoliation of the clay particles. The PVDF matrix is found to be exclusively of the α-form in all compositions. The final microhardness slightly increases with both nanoclay content and degree of crystallinity.

The crosslinking of gelatin using crosslinking agents based on condensation of the aldehyde groups and ε-amine groups present in lysine and hydroxylysine rests is a very attractive method reported recently. The present work deals with different films prepared from commercial gelatin of type B and animal origin, aiming at an improvement of physical properties. These films were modified by two plasticizing agents (glycerol, GLY, and poly (vinyl alcohol), PVA) and/or crosslinked by glutaraldehyde (GTA). The number of ε-amino groups present in the gelatin chains, before and after modification, was determined by the method of protein dosage using 2,4,6-trinitro benzene sulfonic acid (TNBS). The addition of the plasticizing and/or crosslinking agents induced a decrease in the number of ε-amino-groups due to the fact that these groups are involved in the physical and/or chemical crosslinking reactions occurring among the different components. The variation of the crosslinking ratio was studied as a function of formulation type, crosslinking nature and GTA concentration. The use of microhardness (H) in this study emphasizes the effect of the crosslinking on the improvement of the micromechanical properties. The study of differential scanning calorimetry reveals that crosslinking induces a drastic decrease of crystallinity in the samples.

The success of processing compatible blends, based on poly(ethylene terephthalate) (PET)/poly(ethylene naphthalene 2,6-dicarboxylate) (PEN)/clay nanocomposites in one step by reactive melt extrusion is described. Untreated clay was first purified and functionalized "in situ" with a compound based on an organic peroxide/sulfur mixture and (tetramethylthiuram disulfide) as the activator for sulfur. The PET and PEN materials were first separately mixed in the molten state with functionalized clay. The PET/4 wt% clay and PEN/7.5 wt% clay compositions showed total exfoliation. These compositions, denoted nPET and nPEN, respectively, were used to prepare new nPET/nPEN nanoblends in the same mixing batch. The nPET/nPEN nanoblends were compared to neat PET/PEN blends. The blends and nanocomposites were characterized using various techniques. Microstructural and nanostructural properties were investigated. Fourier transform infrared spectroscopy (FTIR) results showed that the exfoliation of tetrahedral clay nanolayers is complete and the octahedral structure totally disappears. It was shown that total exfoliation, confirmed by wide angle X-ray scattering (WAXS) measurements, contributes to the enhancement of impact strength and tensile modulus. In addition, WAXS results indicated that all samples are amorphous. The differential scanning calorimetry (DSC) study indicated the occurrence of one glass transition temperature T g, one crystallization temperature T c and one melting temperature T m for every composition. This was evidence that both PET/PEN and nPET/nPEN blends are compatible in the entire range of compositions. In addition, the nPET/nPEN blends showed lower T c and higher T m values than the corresponding neat PET/PEN blends. In conclusion, the results obtained indicate that nPET/nPEN blends are different from the pure ones in nanostructure and physical behavior.

Novel aspects concerning the micromechanical response of amorphous regions confined by crystals in nano-sized domains are illustrated for semicrystalline poly(ethylene terephthalate) (PET), on the basis of microindentation hardness and dynamical mechanical spectroscopy (DMS) analyses (10-3÷60 Hz frequency range for DMS). PET samples were crystallized from the glassy state at low and high temperatures (Tc=100°C and 160°C, respectively) and subsequently recrystallized some degrees above to gain information on the nature of the amorphous regions. DMS at 95°C reveals two segmental relaxation processes ascribed to the interlamellar amorphous regions (slow mode) and to the interstack amorphous pockets (APs) (fast mode) respectively, the latter being the object of the present study. It is shown that recrystallization changes the cooperativity within the APs. At low Tc, an increase in the cooperativity and the free energy barrier for readjustment is found after recrystallization. Room temperature indentation measurements reveal an enhancement of the average hardness value of the amorphous regions, Ha, on samples recrystallized a few degrees above Tc=100°C. The reduced size of the APs regions upon recrystallization is discussed as a relevant parameter giving rise to an enhanced segmental confinement and a parallel hardening. Results for the high Tc material reveal that, in this case, both the cooperativity (measured at 95°C) and Ha (measured at room temperature) decrease upon recrystallization. The influence of the coupling of the APs with the crystal walls, on the relaxation mode and in turn on the mechanical behavior of the material, is envisaged to be a possible mechanism underlying these observations.

No AccessNano- and Micromechanics of PolymersMar 2012Special Forms and ApplicationsGoerg H. Michler, Francisco J. Baltá-CallejaGoerg H. MichlerSearch for more papers by this author, Francisco J. Baltá-CallejaSearch for more papers by this authorhttps://doi.org/10.3139/9783446428447.012SectionsAboutPDF ToolsAdd to FavoritesDownload CitationTrack CitationsCopy LTI LinkPDF key 'share (en)' returned an object instead of string.FacebookTwitterEmailLinkedIn previous chapternext chapter FiguresReferencesRelatedDetails 2012Pages: 501-555Print ISBN: 978-3-446-42767-9eISBN: 978-3-446-42844-7 Copyright & Permissions© 2012 Carl Hanser Verlag GmbH & Co. KGPDF downloadLoading ...

No AccessNano- and Micromechanics of PolymersMar 2012General Importance of Polymers and TrendsGoerg H. Michler, Francisco J. Baltá-CallejaGoerg H. MichlerSearch for more papers by this author, Francisco J. Baltá-CallejaSearch for more papers by this authorhttps://doi.org/10.3139/9783446428447.001SectionsAboutPDF ToolsAdd to FavoritesDownload CitationTrack CitationsCopy LTI LinkPDF key 'share (en)' returned an object instead of string.FacebookTwitterEmailLinkedIn previous chapternext chapter FiguresReferencesRelatedDetails 2012Pages: 1-33Print ISBN: 978-3-446-42767-9eISBN: 978-3-446-42844-7 Copyright & Permissions© 2012 Carl Hanser Verlag GmbH & Co. KGPDF downloadLoading ...

No AccessNano- and Micromechanics of PolymersMar 2012Nanostructured PolymersGoerg H. Michler, Francisco J. Baltá-CallejaGoerg H. MichlerSearch for more papers by this author, Francisco J. Baltá-CallejaSearch for more papers by this authorhttps://doi.org/10.3139/9783446428447.011SectionsAboutPDF ToolsAdd to FavoritesDownload CitationTrack CitationsCopy LTI LinkPDF key 'share (en)' returned an object instead of string.FacebookTwitterEmailLinkedIn previous chapternext chapter FiguresReferencesRelatedDetails 2012Pages: 415-500Print ISBN: 978-3-446-42767-9eISBN: 978-3-446-42844-7 Copyright & Permissions© 2012 Carl Hanser Verlag GmbH & Co. KGPDF downloadLoading ...

You have accessNano- and Micromechanics of PolymersMar 2012Nano- and Micromechanics of PolymersGoerg H. Michler, Francisco J. Baltá-CallejaGoerg H. Michler, Francisco J. Baltá-Callejahttps://doi.org/10.3139/9783446428447.fmSectionsAboutPDF ToolsAdd to FavoritesDownload CitationTrack CitationsCopy LTI LinkPDF ShareFacebookTwitterEmailLinkedIn next chapter FiguresReferencesRelatedDetails 2012Pages: I-XVIIIPrint ISBN: 978-3-446-42767-9eISBN: 978-3-446-42844-7 Copyright & Permissions© 2012 Carl Hanser Verlag GmbH & Co. KGPDF DownloadLoading ...

No AccessAtlas of Polymer StructuresJan 2016Rubber-Toughened PolymersGoerg H. MichlerGoerg H. MichlerSearch for more papers by this authorhttps://doi.org/10.3139/9781569905586.008SectionsAboutPDF ToolsAdd to FavoritesDownload CitationTrack CitationsCopy LTI LinkPDF key 'share (en)' returned an object instead of string.FacebookTwitterEmailLinkedIn previous chapternext chapter FiguresReferencesRelatedDetails 2015Pages: 331-426Print ISBN: 978-1-56990-557-9eISBN: 978-1-56990-558-6 Copyright & Permissions© 2016 Carl Hanser Verlag GmbH & Co. KGPDF downloadLoading ...

Contract grant sponsor: Spanish Ministry of Science and Innovation (MICINN); contract grant numbers: FIS2010- 18069, MAT2009-00789. Contract grant sponsors: Alexander von Humboldt Foundation, Germany, EC Research Infrastructure (FP6 Program) (Desy Project II-07-031 EC).

No AccessNano- and Micromechanics of PolymersMar 2012Methods and Investigation TechniquesGoerg H. Michler, Francisco J. Baltá-CallejaGoerg H. MichlerSearch for more papers by this author, Francisco J. Baltá-CallejaSearch for more papers by this authorhttps://doi.org/10.3139/9783446428447.002SectionsAboutPDF ToolsAdd to FavoritesDownload CitationTrack CitationsCopy LTI LinkPDF key 'share (en)' returned an object instead of string.FacebookTwitterEmailLinkedIn previous chapternext chapter FiguresReferencesRelatedDetails 2012Pages: 35-93Print ISBN: 978-3-446-42767-9eISBN: 978-3-446-42844-7 Copyright & Permissions© 2012 Carl Hanser Verlag GmbH & Co. KGPDF downloadLoading ...

No AccessNano- and Micromechanics of PolymersMar 2012Fracture Phenomena and MechanismsGoerg H. Michler, Francisco J. Baltá-CallejaGoerg H. MichlerSearch for more papers by this author, Francisco J. Baltá-CallejaSearch for more papers by this authorhttps://doi.org/10.3139/9783446428447.005SectionsAboutPDF ToolsAdd to FavoritesDownload CitationTrack CitationsCopy LTI LinkPDF key 'share (en)' returned an object instead of string.FacebookTwitterEmailLinkedIn previous chapternext chapter FiguresReferencesRelatedDetails 2012Pages: 159-182Print ISBN: 978-3-446-42767-9eISBN: 978-3-446-42844-7 Copyright & Permissions© 2012 Carl Hanser Verlag GmbH & Co. KGPDF DownloadLoading ...