We here demonstrate the effects of solvents on crosslinking and surface characteristics of Urushi (Oriental lacquer) films. We aimed to clarify the influence of solvents on crosslinking of Urushi by comparing normal Urushi films with Urushi films blended with three types of solvents, camphor, turpentine, and methanol, by using differential scanning calorimetry (DSC). In addition, we evaluated the effects of ultraviolet (UV) irradiation on crosslinking and surface characteristics of Urushi films using scanning probe microscopy (SPM) and Fourier transform infrared (FTIR) spectroscopy. The DSC results showed that Urushi films blended with camphor had large amounts of non-crosslinked parts compared to films blended with turpentine and methanol. From the results of SPM observations, it was found that surface roughness increased with an increase in UV irradiation time. Furthermore, FTIR results indicated that CO stretching peaks attributed to the curing reaction increased with an increase in UV irradiation time. This tendency of increasing peak intensity is consistent with the change in surface roughness induced by UV irradiation.

Heat sealing properties are optimized by controlling temperature, pressure and dwell time, while film strength depends on the drawn ratio and the molecular orientation of the film. However, heat seal strength of polymer films with high drawn ratio shows lower peel strength, because the adhesion of films needs a higher heat sealing energy for molecular orientation relaxation at heat sealing. In the present study, polypropylene films with a drawn ratio of 1.0×, 1.5×, and 2.5× are heat sealed by using the heat sealing technique. The heat sealing condition is set to heat sealing time 1.0 s, sealing pressure 0.2 MPa, and heat sealing temperature 145°C. The effect of drawn ratio and stabilization temperature of PP films for peel strength are investigated using T-Peel test, DSC, FT-IR, and Raman spectroscopy. As a result, it is found that the peel strength is decreased with increasing the drawn ratio and stabilization temperature of PP films. The difference of ?H and melting point from the result of DSC measurement are exhibited for 1.5× drawn ratio film as compared with 2.5× one. In addition, FT-IR imaging and Raman line mapping reveal the influence and variation of high order structure for heat sealed parts of the drawn PP films.

In this study, oriented polypropylene/cast polypropylene (OPP/CPP) laminated films were heat sealed by various stainless mesh sheets in order to evaluating the effect of heat sealing bar shape on heat sealed properties. The heat sealed conditions were set at heat sealed time of 1.0 s with a pressure of 0.3 MPa at various heat sealed temperatures of 100 to 120 degrees C. The difference of higher order structure of these films was discussed on the basis of results of micro-Raman spectroscopy, DSC and peel test. From the result, it was found that peel strength was affected by the heat sealing bar surface shape. It can be note that the relationship between the internal structure change and properties of the heat sealed films could be clarified by analyzed at very small area of the heat sealed films on the basis of the results by using micro-Raman spectroscopy imaging.

The deterioration mechanism of polyethylene with increased temperature resistance (PERT) used for hot water supply plumbing was investigated. The deterioration in 120 degrees C air was analyzed by using FT-IR. The following results were found (1) Degradation begins from the place where orientation relaxes gently and the amount of antioxidants decreases. The degradation by oxidation starts from surface. It advances along the surface, but does not advance that much into the bulk. (2) The progress of surface deterioration can be evaluated by the ratio acid to aldehyde peak of the carbonyl group, (3) It is necessary to evaluate not only the amount of carbonyl groups, at around 1600 cm(-1) but also its type (acid or aldehyde). The above result correlate with the results of tensile-strength tests and thermal measurements. The deterioration process of PERT can be analyzed more clearly by the FT-IR imaging method and visualization in two dimensions.

In this investigation, we have succeeded in measurement of minimal-change of polyethylene (PERT) specimens under acceleration degradation test using the ATR-IR method with heating stage. The results of FT-IR corresponded to results of OIT (Oxidative Induction Time) measurement by using DSC. That is, activation energy in DSC was lower than that of FT-IR, and the strong tendency was indicated for the specimens which were severely degraded.FT-IR method allows simultaneous measurement for oxidation degradation time and microstructure spectra of PERT. Therefore, difference of ratio in oxidation products and difference of oxidation reaction process was clarified by comparing results of the acceleration degradation test and results of ATR-IR method with heating stage. In addition, it was found that ATR-IR method with heating stage makes it easy to measure minimal-change of internal structure in specimens, moreover the method makes it possible to apply to analysis of the oxidation degradation.

Different types of nonionic vesicles were prepared from commercial Span 80 (also called sorbitan monooleate), as an inexpensive, biocompatible alternative to conventional phospholipid-based vesicles (liposomes). The vesicles were characterized by different techniques and comparison was made with vesicles formed from POPC (1-palmitoyl-2-oleoyl- sn-glycero-3-phosphocholine) or DOPC (1,2-dioleoyl- sn-glycero-3-phosphocholine). Dynamic light scattering measurements, electron microscopy analyses, and two types of fusion assays indicate that Span 80 vesicles are stable for at least 7 days at 4 or 25 degrees C, while storage at 42 degrees C causes irreversible vesicle fusion. This indicates that Span 80 vesicles are thermoresponsive with vesicle fusion occurring at elevated temperature. This property may be related to headgroup dehydration and is certainly not directly linked to the phase transition temperature (Tm) of the vesicles, since the Tm is below -30 degrees C, as determined by differential scanning calorimetry (DSC). The measured Tm value for Span 80 vesicles is lower than in the case of DOPC or POPC, correlating with a higher fluidity of Span 80 vesicles as compared to POPC or DOPC vesicles, as determined with DPH (1,6-diphenyl-1,3,5-hexatriene) as fluorescent membrane probe. High fluidity correlates with increased leakage of entrapped water-soluble dye molecules. Addition of cholesterol and soybean phosphatidylcholine lowers the extent of leakage, allowing a tuning of the bilayer permeability.

Heat sealing is currently a standard method for manufacturing plastic bags of polylactic acid film, which has high clarity and strength. However, the heat sealing of polylactic acid is difficult because its strength declines at high temperatures. Processing conditions such as the heat sealing temperature and pressure can greatly affect the mechanical properties of the heat sealed part. In this study, the relationship between the heat sealing temperature and the mechanical properties of heat-sealed polylactic acid film were examined through peel strength tests and tensile testing of samples with circular notches. Differential scanning calorimetry (DSC) and FT-IR imaging were used to investigate the dependence of crystallinity and molecular-orientation ratio (MOR) on the heat sealing temperature. These studies showed that the optimum heat seal temperature was 128°C, with a very narrow temperature window. Thus, precise control of the heat sealing temperature is required for polylactic acid plastic bag manufacture.

Failure criteria of the heat-sealed part of oriented polypropylene (OPP) and cast polypropylene (CPP) heat seals made by an impulse type heat-sealing machine were investigated. Circular notches and precracks were introduced to direct failure to specific areas such as inside the seal, at the border, or at the unsealed part. The notched strength as a function of heat-sealing temperature revealed that the seals were stronger in the transverse direction (TD) as compared with the machine direction (MID). Tensile failure that occurred inside the heat seal is more sensitive to sealing temperature, whereas that at the unsealed part is immune. The stress intensity factor (K,) is generally higher along the TD. At high sealing temperatures, i.e. above 150 degrees C, orientation in the OPP film is relaxed and this results in consistently low mechanical properties at this temperature range. This morphology was revealed by studies of crystalline orientation state and FTIR imaging.

The effect of heat sealing temperature on the mechanical properties and morphology of OPP/CPP laminate films was investigated. The laminated films were placed in an impulse type heat sealing machine with both CPP sides facing each other. The temperatures investigated ranged from 100 to 250 degrees C. T-peel and tensile tests in combination with SEM were used to characterize the heat seats. A minimum seal initiation temperature of 120 degrees C was identified for OPP/CPP laminate heat sealing. Peel strength increased sharply from zero at 110 degrees C to maximum at 120 degrees C, after which a gradual decrease was observed. Tensile strength initially increased until 120 degrees C, after which it gradually decreased until 170 degrees C and assumed a constant value beyond that. The initial rise has been associated to cold crystalization, while the reduction between 120 degrees C and 170 degrees C was due to relaxation in molecular orientation. Beyond 170 degrees C, all the orientation in the laminate has been lost so orientation effects are nullified. Morphological studies with SEM revealed that seals were partially formed at lower temperatures, while the laminates were totally fused together at high temperatures, with intermediate temperatures showing properties that lie in between. (c) 2005 Wiley Periodicals, Inc.

A previous study has shown that the adhesion between the film and substrate of film-insert injection-molded poly(propylene) (PP) film/PP substrate was evident with the increases in barrel temperature and injection holding pressure. In this second part of the research work, the crystallinity at the interfacial region (i.e., region between the film and the injected substrate) was extensively studied using FTIR imaging, polarized light microscopy, and DSC in an attempt to determine the level of influence that crystallinity has on the interface and bulk mechanical properties. Consequently, a more thorough and clearer picture of the influence of the inserted film on the interfacial crystallinity and subsequently the substrate mechanical properties, such as peel strength and impact strength, has been revealed. The initial proposition that crystallinity could enhance film-substrate interfacial bonding has been confirmed, judging from the higher peel strength with increasing crystallinity at the interfacial region. Nevertheless, the change in crystallinity was not only confined to the interfacial region. With the film acting as heat-transfer inhibitor between the injected resin and the mold wall, the total crystal structure of the substrate was substantially altered, which subsequently affected the bulk mechanical properties. The lower impact strength of film-insert injection-molded samples compared to that of samples without film inserts provided evidence of how the film could impart inferior properties to the substrate. The difference in cooling rate between the substrate and film might also cause other defects such as warpage and/or residual stress build-up within the product. (c) 2005 Wiley Periodicals, Inc.

The crystalline Structure of the heat-sealed part of oriented polypropylene (OPP) and cast polypropylene (CPP) films was investigated by differential scanning calorimetry, Fourier transform infrared spectroscopy, and thermal mechanical analysis (TMA). The relationship between the crvstalline structure and the mechanical properties was analyzed. It was found that the high total crystallinity of both OPP and CPP gave rise to good mechanical properties and that the orientation of the crystalline structure in the OPP film also was an important factor. The optimum condition for heat sealing was the temperature at which total crystallinity was highest while still retaining the crvstalline orientation of OPP. The assessment of crystalline orientation by TMA is an innovation initiated by the authors. (c) 2005 Wiley Periodicals, Inc.

order to clarify the relationship between heat-sealing conditions and the strength of the heat-sealed part, the crystalline structure of the heat-sealed part of the film was evaluated by differential scanning calorimetry (DSC) and Fourier transform infrared (FT IR) spectroscopy. The laminated films that include a biaxially oriented nylon (ONY) film and a cast linear low-density polyethylene (LLDPE) film with an appropriate adhesive were heat-sealed by using an impulse type heat-sealer. First the possibility of adhesion was examined by changing the processing conditions and the maximum temperature was measured. As for mechanical properties, a peel strength test was performed to evaluate the strength of the heat-sealed parts. However, the strength could not be evaluated by the peeling test alone, because the fracture shifted from the heat-sealed part to the edge of the heat seal accompanied by necking and yielding of the film. In order to solve this problem, a tensile specimen with a semicircular notch was proposed to evaluate the strength of the heat-sealed part. Tensile strength increased with increasing crystallinity of the LLDPE indicated by the melting peak in the DSC measurement and FT IR spectra. It was found that crystallinity profoundly affected the mechanical properties of the heat-sealed part.

The effects of barrel temperature and injection rate on the interfacial mechanical and morphological properties of film-insert injection-molded PP-film/PP matrix were investigated. In high barrel temperature and injectionrate, film did not peel from the injected PP. In this situation, the surface of the film was found to have melted by the heat of injected PP, which resulted in higher crystallinity of PP film near the interface. On the other hand, in low barrel temperature and injection rate, the film peeled from the substrate. In this situation, crystallinity of the surface of the film was found to be low because the heat of the injected PP did not affect the film.

As a packaging material, plastic film is widely used in daily life to protect merchandise while improving their marketing appeal. There are many cases when the plastic film packaging is formed into bags by heat sealing the edges. In order to discuss the properties of the heat-sealed portion of these plastic film bags, oriented polypropylene film OPP and cast polypropylene film (CPP) were heat-sealed, and the strength and crystalline structure of the heat sealed regions were investigated. The strength was obtained from peel tests according to JIS Z 1707 and from tensile tests for circular notched specimens. The crystalline structure was analyzed by differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FT-IR). The crystallinity of the heat-sealed part affected the tensile strength. When the crystallinity of OPP was high, the strength obtained from the tensile test for circular notched specimens was high, and the relation between crystallinity and the strength could be established.

In order to clarify the optimal conditions for heat sealing of a plastic film, the expansion and contraction properties in the thickness direction of a film were examined with thermomechanical analysis (TMA). Specimens consisting of a biaxially oriented polypropylene (OPP) film and a cast polypropylene (CPP) film were made from laminated films used abundantly for packing. The heat sealing temperature was varied while the films were sealed at constant pressure by an impulse type heat sealer. TMA revealed that the compression behavior in the thickness direction of the heat-sealed laminated film was influenced by the relaxation of the orientation properties of the OPP layer. The compression TMA curves and DSC curves agreed well. Furthermore, the results of TMA and DSC indicated the existence of an oriented state of the film after heat sealing. It was suggested that relaxation of the molecule orientation in biaxially oriented OPP films led to the phenomenon of decreased tensile strength under 160°C heat sealing temperatures.

The molding condition and mechanical properties of the unidirectional UHMW-PE fiber reinforced linear lowdensity polyethylene (LLD-PE) composites were investigated. The most important fabrication parameter of thermoplastic materials used for such a composite was molding temperature. First differential scanning calorimetry (DSC) (thermal analysis) was performed and the melting point for UHMW-PE fiber and PE matrix film was measured. Mechanical properties of UHMW-PE fiber by high heat treatment were investigated. Then, simulate DSC measurements were performed for specimens subjected to several types of thermal history. Time-temperature profile in simulate DSC measurements referred to the actual processing conditions. The effects of molding temperature on mechanical properties were investigated. At the molding temperature observed re-fusion peak of UHMWPE fiber in DSC measurements, mechanical properties in longitudinal direction was maintained. On the other hand, mechanical properties in transverse direction were highest value. From these results comparing with the theoretical value by Law of mixture, it is considered that interfacial properties of PE/PE composites were changed by the molding temperature. PE/PE composites with optimum molding condition could be fabricated by using the suitable molding temperature between PE fiber and matrix.

A metal-to-insulator transition in CaVOy by varying the oxygen stoichiometry is reported. Stoichiometric CaVOy (y=3.00) shows good metallic conductivity but slight oxidation (y≅3.05) causes the system to be insulating without any significant structural changes. This behavior is contrary to that seen in another d1 system LaTiOy, which is a Mott insulator for y=3.00 but becomes metallic by oxidation. We suggest that, in CaVOy, oxygen defects primarily induce additional scattering which causes the metallic CaVO3 to be insulating rather than add extra carriers.

The weight-change behaviour of the fibre/matrix interface in composite panels consisting of randomly orientated E-glass-fibre continuous strand mat in unsaturated polyester has been studied. Two matrix resins of different filler content were used. GRP and plain resin specimens were immersed in hot water (60°C and 80°C) and the weight of the specimens was measured as a function of time. The weight changes were evaluated in terms of three parameters: apparent weight gain, net weight gain and weight loss. The weight changes of the fibre/matrix interface were obtained from the differences in the weight changes of the GRP and the unreinforced resin. Water absorption at the interface occurred after water absorption of the matrix resin reached almost saturation level. Weight loss due to dissolution of binder from the interface occurred after water penetration into the interface. Debonding occurred at the fibre/matrix interface as a result of water penetration, and, in consequence, the binder dissolved into water at the interface. The net weight gain and weight loss of the interface increased linearly with the square root of immersion time, and the filler had little effect on these phenomena.