Preparation and characterization of konjac glucomannan and sodium carboxymethylcellulose blend films

The novel blend films of konjac glucomannan (KGM) and sodium carboxymethylcellulose (NaCMC) were prepared by casting the mixed polymer aqueous solutions. The physical properties of the blend films from konjac glucomannan and sodium carboxymethylcellulose were investigated by using FT‐infrared (FTIR), wide‐angle X‐ray diffraction (WAXD), differential thermal analysis (DTA), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and measurements of mechanical properties. The experimental results showed that the occurrence of the interactions between KGM and NaCMC molecular chains through hydrogen bond formation, and the physical properties of the films largely depend on the blending ratio. The thermal stability, mechanical properties of both tensile strength, and elongation at break of the blend films were improved by blending KGM with NaCMC. The surface morphology of the films observed by SEM was consistent with the results mentioned above. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 26–31, 2001     

Mechanical and Transport Properties of Poly(ethyleneterephthalate) Films with Reference to Sulphur Mustard

Influence of sulphur mustard (SM), a chemical warfare agent, on mechanical and transport properties of poly(ethyleneterephthalate) (PET) films was investigated. The objective of the study was to assess the agent–substrate interaction. SM induces changes in PET in that the elongation as well as strength of SM-exposed films decreases considerably. The reduction in percentage elongation at break is very significant, perhaps because of the antiplasticizing effect of SM on PET. The breakthrough time (BTT) of SM is higher for the film, which showed greater resistance to amine etching. The critical dissolution time measurement substantiates the data on mechanical behaviour of SM-exposed films. © of SCI.     

Graft copolymerization of n-vinyl-2-pyrrolidone on dimethyl sulfoxide pretreated poly(ethylene terephthalate) films using azobisisobutyronitrile initiator

Poly(ethylene terephthalate) (PET) films were grafted with n-vinyl-2-pyrrolidone (n-VP) using an azobisisobutyronitrile (AIBN) initiator. Films were pre-treated in dimethyl sulfoxide (DMSO) for 1 h at 140°C before the polymerization reaction was carried out. Variations of graft yield with time, temperature, initiator, and monomer concentrations were investigated. The optimum temperature and polymerization time was found to be 70°C and 4 h, respectively. Increasing monomer concentration from 0.28 to 1.22M and initiator concentration from 1.77 × 10⁻³ to 4.20 × 10⁻³M enhanced the percent grafting. The effects of monomer and initiator diffusion on PET films were also studied. The overall activation energy for grafting was calculated as 11.5 kcal/mol. Further changes in properties of PET films such as water-absorption capacity and intrinsic viscosity were determined. The grafted films were characterized with FTIR and scanning electron microscopy (SEM). © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 1437–1444, 1997     

Study on physical properties of blend films from gelatin and polyacrylamide solutions

Blend films of gelatin and polyacrylamide (PAAm) were prepared by casting the mixed aqueous solutions of both samples in different ratios. All blend films obtained are optically clear to the naked eye. The structure and physical properties of the films were studied by FT‐infrared (FTIR), wide‐angle X‐ray diffraction (WAXD), differential thermal analysis (DTA), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The experimental results show that the blend films exhibit the higher thermal stability and improved mechanical properties of both tensile strength and elongation at break in dry states, which suggests the occurrence of interaction detected by FTIR between gelatin, PAAm, and water molecules in the films. The morphological transition of the blend films from gelatin‐like to PAAm‐like was observed by SEM. Furthermore, moisture content and water swelling property of the blend films were also investigated, which was consistent with the results from SEM. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 949–955, 2002     

Preparation and physical properties of konjac glucomannan–polyacrylamide blend films

The blend films of konjac glucomannan (KGM) and polyacrylamide (PAAm) were prepared by using the solvent‐casting technique. Transparent blend films were obtained in all blending ratios. The physical properties of the films were investigated by Fourier transform infrared spectroscopy, wide‐angle X‐ray diffraction, thermogravimetric analysis, scanning electron microscopy, and by measurement of mechanical properties. The results indicated the occurrence of intra‐ and intermolecular interactions of the pure components, as well as the intermolecular interactions between KGM and PAAm through hydrogen bond formation. The thermal stability and mechanical properties of both tensile strength and elongation at break of the films were improved by blending KGM with PAAm. It was worth noting that the blend film had the greatest tensile strength when the KGM content in the blend films was around 30 wt %. Surface morphology of the films observed by SEM was consistent with the above‐noted results. Furthermore, the water absorbability of the blend films was also investigated. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 882–888, 2001     

Tensile and dynamic mechanical properties of improved ultrathin polymeric films

Tensile and dynamic mechanical properties of improved ultrathin polymeric films for magnetic tapes are presented. These films include poly(ethylene terephthalate) or PET, poly(ethylene naphthalate) or PEN, and aromatic polyamide (ARAMID). PET film is currently the standard substrate used for magnetic tapes; thinner tensilized‐type PET, PEN, and ARAMID were recently used as alternate substrates with improved material properties. The thickness of the films ranges from 6.2 to 4.8 μm. Young's modulus of elasticity, F5 value, strain‐at‐yield, breaking strength, and strain‐at‐break were obtained at low strain rates by using a tensile machine. Storage (or elastic) modulus, E′, and the loss tangent, tan δ, which is a measurement of viscous energy dissipation, are measured by using a dynamic mechanical analyzer at temperature ranges of ?50 to 150°C (for PET), and ?50 to 210°C (for PEN and ARAMID), and at a frequency range of 0.016 to 29 Hz. Frequency–temperature superposition was used to predict the dynamic mechanical behavior of the films over a 28 decade frequency range. Results show that ARAMID and tensilized films tend to have higher strength and moduli than standard PET and PEN. The rates of decrease of storage modulus as a function of temperature are lower for PET films than those for PEN and ARAMID films. Storage modulus for PEN films are higher than that for PET films at high frequencies, but this relationship reverses at low frequencies. ARAMID has the highest modulus and strength among the films in this study. The relationship between polymeric structure and mechanical properties are also discussed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2225–2244, 2002     

Mechanical,hygroscopic, and thermal properties of ultrathin polymeric substrates for magnetic tapes

Mechanical, hygroscopic, and thermal properties of improved ultrathin polymeric films for magnetic tapes are presented. These films include poly(ethylene terephthalate) (PET), poly(ethylene naphthalate) (PEN), and aromatic polyamide (ARAMID). PET films are currently the most commonly used polymeric substrate material for magnetic tapes, followed by PEN and ARAMID. The thickness of the films ranges from 6.2 to 4.8 μm. Tensile tests were run to obtain the Young's modulus, F5 value, strain at yield, breaking strength, and strain at break. The storage modulus, E′, and the loss tangent, tan δ, were measured using a dynamic mechanical analyzer (DMA) at temperature ranges of ?50 to 150°C (for PET) and ?50 to 210°C (for PEN and ARAMID) and at a frequency range of 0.016–28 Hz. Frequency–temperature superposition was used to predict the dynamic mechanical behavior of the films over a 28‐decade frequency range. Short‐term longitudinal creep behavior of the films during 10, 30, 60, and 300 s, 7 MPa, were measured at 25 and 55°C. Long‐term longitudinal creep measurements were performed at 25, 40, and 55°C for 100 h. The Poisson's ratio and 50‐h long‐term lateral creep were measured at 25°C/15% RH, 25°C/50% RH, 25°C/80% RH, and 40°C/50% RH. The in‐plane coefficient of hygroscopic expansion (CHE) at 25°C/20–80% RH and the coefficient of thermal expansion (CTE) at 30–70°C were measured for all the samples. The properties for all films are summarized. The relationship between the polymeric structure and the mechanical and physical properties are discussed, based on the molecular structure, crystallinity, and molecular orientation. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3052–3080, 2003     

Characterization of konjac glucomannan–gelatin blend films

Novel blend films of konjac glucomannan (KGM) with gelatin were prepared by using the solvent‐casting technique. Transparent blend films were obtained in all blending ratios of the two polymers. The structure and physical properties of the films were investigated by Fourier transform IR, wide angle X‐ray diffraction, thermogravimetric analysis, differential thermal analysis, scanning electron microscopy (SEM), and strength tests. The results indicated that intermolecular interactions between the KGM and gelatin occurred that were caused by hydrogen bonding and the physical properties of the films largely depended on the blending ratio. The crystallinities of the blend films decreased with the increase of the KGM. The thermal stability and mechanical properties (tensile strength and elongation at break) of the films were improved by blending KGM with gelatin. It is worth noting that the blend films had a good tensile strength of 38 MPa when the KGM content in the blend films was around 30 wt %. The surface morphology of the blend films observed by SEM displayed a certain level of miscibility. Furthermore, the water absorbability of the blend films was also measured and discussed. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1596–1602, 2001     

The effect of accelerated weathering on the degradation of polymeric films

The influence of artificial weathering on three general properties of films of high-impact polystyrene (HIP), poly(ethylene terephthalate) (PET), and poly(vinyl chloride) (PVC) was investigated, Degradation resulting from weathering was investigated in terms of changes in the water vapor permeation, mechanical properties, and optical transmission. The diffusivities and permeabilities of these three materials were significantly altered by weathering at two levels of exposure. Films of HIP were embrittled at both levels of exposure, whereas the PET films were embrittled only at the high level of exposure. Films of PVC showed embrittlement at the highest level of exposure and the lowest test temperature. Changes in the optical properties were less significant, amounting to a relatively small decrease in the transmission of the films in the visible range.     

Photodegradation of multilayer films based on PET copolymers

An investigation was conducted on the effects of photodegradation of multilayer films based on PET copolymers. The films were composed by different layers with PET, PET/PEN, and PET/PEI copolymers with a total thickness of 23 μm. The films produced by coextrusion followed by a biaxial orientation in an industrial equipment were exposed to the ultraviolet radiation in the laboratory for periods of up to 600 h. The samples were investigated by FTIR‐ATR, UV/visible spectroscopy, fluorescence spectroscopy, size exclusion chromatography, mechanical properties, and scanning electron microscopy. The results showed that the photooxidation is concentrated at the surface layers and that coextruded films were more sensitive to the UV radiation effects. The deterioration in mechanical properties with exposure and the fracture behavior were shown to be consistent with the amount of degradation that occurred in the films. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Study on microstructure of PET/nanopowder composites

In this article, the microstructures of polyethylene terephthalate (PET)/nanopowder of butadiene‐styrene‐vinylpyridine (BSV) rubber, PET/nanocalcium carbonate, and PET/nanoorganoclay as well as the effects of mechanical properties and crystallization on PET were investigated. Scanning electron microscope (SEM) indicated that when the nanoparticles are added into PET, small spheroidicity‐shaped particles were seen in the SEM micrographs, and these particles were not nanopowders themselves. The crystallization of PET is improved with the incorporation of proper quantity of nanopowders of BSV and nanoorganoclay. Nanopowders of BSV and organoclay can enhance PET's mechanical properties but not the nanocalcium carbonate. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Morphology and barrier mechanism of biaxially oriented poly(ethylene terephthalate)/poly(ethylene 2,6‐naphthalate) blends

To improve the barrier properties of poly(ethylene terephthalate) (PET), PET/poly(ethylene 2,6‐naphthalate) (PEN) blends with different concentrations of PEN were prepared and were then processed into biaxially oriented PET/PEN films. The air permeability of bioriented films of pure PET, pure PEN, and PET/PEN blends were tested by the differential pressure method. The morphology of the blends was studied by scanning electron microscopy (SEM) observation of the impact fracture surfaces of extruded PET/PEN samples, and the morphology of the films was also investigated by SEM. The results of the study indicated that PEN could effectively improve the barrier properties of PET, and the barrier properties of the PET/PEN blends improved with increasing PEN concentration. When the PEN concentration was equal to or less than 30%, as in this study, the PET/PEN blends were phase‐separated; that is, PET formed the continuous phase, whereas PEN formed a dispersed phase of particles, and the interface was firmly integrated because of transesterification. After the PET/PEN blends were bioriented, the PET matrix contained a PEN microstructure consisting of parallel and extended, separate layers. This multilayer microstructure was characterized by microcontinuity, which resulted in improved barrier properties because air permeation was delayed as the air had to detour around the PEN layer structure. At a constant PEN concentration, the more extended the PEN layers were, the better the barrier properties were of the PET/PEN blends. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1309–1316, 2006     

Surface nature of UV deterioration in properties of solid poly(ethylene terephthalate)

We investigated the changes in the molecular weight and also in the mechanical properties with the distance to the exposed surface of the irradiated stacked poly(ethylene terephthalate) (PET) film samples. A relation between the molecular weight and the mechanical properties of the irradiated PET was established. The relation demonstrates that the decrease in molecular weight is one of the main origins causing the deterioration in the mechanical properties. The photodegradation process developing in PET was quantitatively studied by investigating the degradation kinetics of stacked PET film samples. Our results show that the strongest degradation takes place at the exposed surface, and the degradation rate decreases with increasing the distance. This further implies that the capability to bear a tensile stress in the area near the exposed surface is much lower than that in bulk. Therefore, irradiated PET may be fractured in a lower stress. These results indicate the surface nature of ultraviolet deterioration in the physical properties of PET. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67: 705–714, 1998     

Influence of the Addition of Tetrabutyl Orthotitanate on the Rheological,Mechanical, Thermal,and Morphological Properties of Polycarbonate/Poly(Ethylene terephthalate) Blends

The effects of the incorporation of tetrabutyl orthotitanate (TBOT) on the mechanical, thermal, rheological, and morphological properties of polycarbonate (PC)/ poly(ethylene terephthalate) PET blends were investigated. Blends were prepared using a screw extrusion with TBOT's rates varying from 0 to 0.25 phr. Rheological and mechanical investigations showed that the blends properties decreased by chain scissions induced by the degradation of PET and by volatile products release. Differential scanning calorimetry (DSC) revealed that the crystallinity of PET in PC/PET blends is affected by many parameters and does not depend only on PC and TBOT concentrations whereas dynamic mechanical analysis (DMA) and scanning electron microscopy (SEM) support the occurrence of a little compatibilization.     

Surface and barrier properties of hybrid nanocomposites containing silica and PEO segments

Hybrid organic–inorganic nanocomposites containing PEO segments linked to a methacrylate network were prepared through a dual‐curing process, which involved photopolymerization and condensation of alkoxysilane groups. A system based on an α,ω‐dimethacrylate PEO oligomer (BEMA 1400) added with methacryloyl‐oxypropyl‐trimethoxysilane (MEMO) and tetraethoxysilane (TEOS) was used. The surface properties of the obtained films were investigated through XPS analyses and contact angle measurements. A selective enrichment of the MEMO additive towards the outermost layers of the films was evidenced either in the presence or in the absence of TEOS. SEM analyses were performed on the cross section of the films coated on PET substrates, determining the film composition at different depth by EDS analysis. The Si content was found constant, moving from the PET surface towards the air–surface of the films. The barrier properties, with respect to oxygen, of the hybrid films coated on a PET substrate were measured. A decrease of the permeability and of the oxygen transmission rate using hybrid coatings was observed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 4107–4115, 2007     

Investigation of thermal,rheological, and physical properties of amorphous poly(ethylene terephthalate)/organoclay nanocomposite films

Thermal, rheological, and physical properties of amorphous poly(ethylene terephthalate) (PET)/organoclay nanocomposite films which were successfully prepared with melt processing method using a PET/organoclay masterbatch were studied in detail. Structural and physical properties of the films were characterized by the UV–Vis spectroscopy, XRD and SEM analysis, DSC, DMA, and rheological tests and gas permeability measurements. Cold‐crystallization behavior of the samples was analyzed by the DSC and DMA methods. Aspect ratio of the organoclay layers were determined with the Nielsen and Halpin‐Tsai models based on the gas permeability and DMA data, respectively. It was found that the organoclay reduced the nonisothermal cold‐crystallization rate of PET chains by restricting the segmental motion of the polymer in the solid state. On the other hand, the organoclay enhanced the nonisothermal melt‐crystallization of PET due to the nucleation effect. Aspect ratio (A_f) of the clay layers were found to be about 20 by using the gas permeability and DMA data. Aspect ratio value was also confirmed by the analysis of SEM images of the samples. A physical model for the sample microstructure was offered that the stacks with the thickness of 20–30 nm and the lateral size of 400–600 nm, probably consisting of 5–8 layers, were uniformly dispersed in the PET structure. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Polyethylene terephthalate/calcined kaolin composites: Effect of uniaxial stretching on the properties

This article is aimed at investigating the effect of a calcined kaolin filler (CKao) on polyethylene terephthalate (PET). The influence of a silane coupling agent, chain extension, and post extrusion uniaxial hot‐stretching on the final properties of the produced composites were studied as well. PET‐CKao films were prepared via melt blending using a twin‐screw extruder followed by stretching above the glass transition temperature at controlled conditions. The morphology of the composites before and after stretching was observed by SEM. Rheological measurements were also performed to characterize the polymer melts. Mechanical and optical properties as well as the oxygen transmission rate of the composites were also investigated. The results showed that addition of CKao particles, even at low filler content, improved drastically the mechanical and barrier properties compared to the neat PET. This effect was more pronounced in case of hot‐stretched samples. The main drawback observed with these CKao particle composites was an increased haze. Processing parameters including stretching temperature and stretching ratio were found to have a significant effect on the final properties; however, the influence of the stretching rate was negligible. POLYM. ENG. SCI., 55:1767–1775, 2015. © 2014 Society of Plastics Engineers     

Improving the oxygen barrier properties of polyethylene terephthalate by graphite nanoplatelets

Enhancement of the oxygen gas barrier properties of polyethylene terephthalate (PET), used in the packaging industry, is the main objective here. For this purpose, nanocomposites of PET containing graphite nanoplatelets (GNPs) were prepared by melt compounding. The effects of the nanocomposites' structural morphology on oxygen gas permeability were analyzed using a range of thermal, microscopic, and mechanical characterization techniques. The investigated nanocomposite films exhibited GNP exfoliated morphology and good mixing with PET, as well as uniform dispersion within the polymer. All nanocomposite films were shown to possess superior oxygen barrier properties and improved thermal and dimensional stability compared with the plain PET films. In the best case, for 1.5 wt % GNP, the oxygen permeation was reduced by more than 99%. The improved barrier properties are attributed to the direct effect of the GNPs and to their induced increase of degree of crystallinity. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Preparation and characterization of poly(propylene carbonate)/exfoliated graphite nanocomposite films with improved thermal stability,mechanical properties and barrier properties

Relatively high aspect ratio exfoliated graphite (EFG) particles with an average size of 7.4 µm and a nanometer sized thickness of 30–50 nm were successfully prepared by thermal treatment at 1050 °C and subsequent ultrasonication for application as a filler to improve the physical properties of eco‐friendly poly(propylene carbonate) (PPC). A series of poly(propylene carbonate)/exfoliated graphite (PPC/EFG) nanocomposite films with different EFG contents were prepared via a solution blending method. The physical properties were strongly dependent upon the chemical and morphological structures originating from the differences in EFG composition. The morphological structures, thermal properties, mechanical properties and barrier properties of the nanocomposite films were investigated as a function of the EFG content. While all of the PPC/EFG nanocomposite films exhibited good dispersion of EFG to some extent, Fourier transform infrared and SEM results revealed that solution blending did not lead to strong interactions between PPC and EFG. As a result, poor dispersion occurred in composite films with a high EFG content. By loading EFG particles, the oxygen permeabilities, moisture permeabilities and water uptake at equilibrium decreased as the EFG content increased. Compared with pure PPC, PPC/EFG nanocomposite films have enhanced molecular ordering. Specifically, the 2% PPC/EFG composite film shows greater molecular ordering than the other composite films, which results in the highest mechanical strength. In future work, the compatibility and dispersion of the PPC matrix polymer and EFG filler particles should be increased by modifying the EFG surface or introducing additives. © 2013 Society of Chemical Industry