Copper metallization of poly(ethylene terephthalate) fabrics via intermediate polyaniline layers

Poly(ethylene terephthalate) fabrics were metallized through electroless plating of copper. The copper plating was performed on palladium-decorated polyaniline surfaces, and polyaniline was present as an intermediate layer on fabrics to facilitate palladium formation. Different oxidation states of polyaniline were tested in their efficacy in Pd (II) reduction and subsequent Cu plating. X-ray photoelectron spectroscopy was used to monitor the surface changes along the metallization procedure, and surface resistance was measure to probe the electrical properties of the metallized fabrics.     

Miscibility and crystallization behaviors of poly(trimethylene terephthalate)/poly(ethylene naphthalate) blends

Poly(trimethylene terephthalate) (PTT)/poly(ethylene naphthalate) (PEN) blends of various compositions were prepared by the solution-blending and melt-blending methods. The changes in miscibility and crystallization behaviors of the blends upon thermal treatment above the melting temperature of the blends at 280°C were investigated by using DSC, DMA,¹H NMR, and SAXS analyses. Without any thermal treatment, the blend systems were not miscible, and the thermal transitions, such as glass transition, cold crystallization, and crystal melting of the individual components were observed in the DSC and DMA analyses. With thermal treatment, though, they became miscible as the thermal transitions of each component disappeared and single glass transition peaks were observed in the thermal analysis. The chain randomness determined using¹H NMR spectroscopy revealed that thermal treatment at 280°C for more than 30 min brought about transesterification reactions between the PTT and PEN segments resulting in an increase in their miscibility. These results were confirmed by the small angle X-ray analysis conducted to determine the long period (L), the thickness of the crystalline lamella stack (l _c ), and the thickness of the amorphous region (l _a ). After short thermal treatment, the melt-blended sample followed the values for the individual components. However, with extended thermal treatment, the blend became homogeneous, possessing different crystalline morphologies which resulted in different values ofL, l _c , andl _a .     

The effect of molecular weight and the linear velocity of drum surface on the properties of electrospun poly(ethylene terephthalate) nonwovens

In this study, we evaluated the effect of the molecular weight of the polymer on electrospun poly(ethylene terephthalate) (PET) nonwovens, and their mechanical properties as a function of the linear velocity of drum surface. Polymer solutions and electrospun PET nonwovens were characterized by means of viscometer, tensiometer, scanning electron microscope (SEM), wide angle X-ray diffraction measurement (WAXD) and universal testing machine (UTM). By keeping the uniform solution viscosity, regardless of molecular weight differences, electrospun PET nonwovens with similar average diameter could be obtained. In addition, the mechanical properties of the electrospun PET nonwovens were strongly dependent on the linear velocity of drum surface. From the results of the WAXD scan, it was found that the polymer took on a particular molecular orientation when the linear velocity of drum surface was increased. The peaks became more definite and apparent, evolving from an amorphous pattern at 0 m/min to peaks and signifying the presence of crystallinity at 45 m/min.     

Synthesis and hydrophilicity of poly(trimethylene 2,6-naphthalate)/poly(ethylene glycol) copolymers

Poly(trimethylene 2,6-naphthalate) (PTN)/poly(ethylene glycol) (PEG) copolymers were synthesized by the two-step melt copolymerization process of dimethyl-2,6-naphthalenedicarboxylate (2,6-NDC) with 1,3-propanediol (PD) and PEG. The copolymers produced had different PEG molecular weights and contents. The structure, thermal property, and hydrophilicity of these copolymers were studied by proton nuclear magnetic resonance (¹H-NMR) analysis, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and by contact angle, moisture content, and instantaneous elastic recovery measurements. The intrinsic viscosity and the instantaneous elastic recovery of the PTN/PEG copolymers increased with increasing PEG molecular weight and content, whereas the glass transition, melting, and cold crystallization temperatures, and the heat of fusion of the PTN/PEG copolymers all decreased with increasing PEG molecular weight or content. The thermal stability of the copolymers was not affected by PEG molecular weight or content. The hydrophilicity, as determined by contact angle and moisture content measurements of the copolymer films, was significantly improved with increasing PEG molecular weight and content.     

Synthesis and hydrophilicities of Poly(ethylene 2,6-naphthalate)/Poly(ethylene glycol) copolymers

Poly(ethylene 2,6-naphthalate) (PEN)/Poly(ethylene glycol) (PEG) copolymers were synthesized by two step reaction during the melt copolymerization process. The first step was the esterification reaction of dimethyl-2,6-naphthalenedicarboxylate (2,6-NDC) and ethylene glycol (EG). The second step was the condensation polymerization of bishydroxyethylnaphthalate (BHEN) and PEG. The copolymers contained 10 mol% of PEG units with different molecular weights. Structures and thermal properties of the copolymers were studied by using¹H-NMR, DSC, TGA, etc. Especially, while the intrinsic viscosities of PEN/PEG copolymers increased with increasing molecular weights of PEG, but the glass transition temperature, the cold crystallization temperature, and the weight loss temperature of the copolymers decreased with increasing molecular weights of PEG. Consequently, the hydrophilicities by means of contact angle measurement and moisture content of the copolymer films were found to be significantly improved with increasing molecular weights of PEG.     

Effects of lipase on poly(lactic acid) fibers

Two types of lipases, L3126 and Lipex 100L, were used to modify the surface of poly(lactic acid) (PLA) fiber by measuring weight loss percentage and wettability of the fiber in this work. The influence factors were discussed and optimized based on single-factor experiments. The optimal conditions for the modification of poly(lactic acid) fiber with lipases were determined as follows: incubation with lipase L3126 of 0.5 g/l at 45 °C and pH 8.5 for 8 hours and incubation with lipase of 10 ml/l at 40 °C and pH 7.5 for 10 hours. Lipase L3126 showed higher biodegradation ability to poly(lactic acid) fiber than lipase Lipex 100L. The scanning electron microscopy confirmed that both of the two lipases could lead to the formation of etching characters on treated poly(lactic acid) fibers in comparison with the blank samples. Furthermore, the wettability of the fibers treated with the lipases was evidently improved, especially Lipase L3126.     

X-ray diffraction studies of poly(aryl ether ether ketone) fibers with different degrees of crystallinity and orientation

A selection of commercially available poly(ethylene terephthalate) fibers with different degrees of molecular alignment and crystallinity have been investigated utilizing a wide range of techniques including optical microscopy, infrared spectroscopy together with thermal and wide-angle X-ray diffraction techniques. Annealing experiments showed increased molecular alignment and crystallinity as shown by the increased values of birefringence and melting enthalpies. Crystallinity values determined from thermal analysis, density, unpolarized infrared spectroscopy and X-ray diffraction are compared and discussed in terms of the inherent capabilities and limitations of each measurement technique. The birefringence and refractive index values obtained from optical microscopy are found to decrease with increasing wavelength of light used in the experiments. The wide-angle X-ray diffraction analysis shows that the samples with relatively low orientation possess oriented non-crystalline array of chains whereas those with high molecular orientation possess well defined and oriented crystalline array of chains along the fiber axis direction. X-ray analysis showed increasing crystallite size trend with increasing molecular orientation. SEM images showed micro-cracks on low oriented fiber surfaces becoming smooth on highly oriented fiber surfaces. Excellent bending characteristics were observed with knotted fibers implying relatively easy fabric formation.     

Improvement of mechanical and electrical properties of poly(ethylene glycol) and cyanoresin based polymer electrolytes

Ionic conductivity and mechanical properties of a mixed polymer matrix consisting of poly(ethylene glycol) (PEG) and cyanoresin type M (CRM) with various lithium salts and plasticizer were examined. The CRM used was a copolymer of cyanoethyl pullulan and cyanoethyl poly(vinyl alcohol) with a molar ratio of 1:1, mixed plasticizer was ethylene carbonate (EC) and propylene carbonate (PC) at a volume ratio of 1:1. The conductive behavior of polymer electrolytes in the temperature range of 298∼338 K was investigated. The PEG/LiClO₄ complexes exhibited the highest ionic conductivity of ∼10⁻⁵ S/cm at 25°C with the salt concentration of 1.5 M. In addition, the plasticized PEG/LiClO₄ complexes exhibited improvement of ionic conductivity. However, their complexes showed decreased mechanical properties. The improvement of ionic conductivity and mechanical properties could be obtained from the polymer electrolytes by using CRM. The highest ionic conductivity of PEG/CRM/LiClO₄/(EC-PC) was 5.33×10⁻⁴ S/cm at 25°C.     

Preparation and characterization of nanoscaled poly(vinyl alcohol) fibers via electrospinning

Nanoscaled PVA fibers were prepared by electrospinning. This paper described the electrospinning process, the processing conditions, fiber morphology, and some potential applications of the PVA nano-fibers. PVA fibers with various diameters (50–250 nm) were obtained by changing solution concentration, voltage and tip to collector distance (TCD). The major factor was the concentration of PVA solution which affected the fiber diameter evidently. Increasing the concentration, the fiber diameter was increased, and the amount of beads was reduced even to 0%. The fibers were found be efficiently crosslinked by glyoxal during the curing process. Phosphoric acid was used as a catalyst activator to reduce strength losses during crosslinking. Scanning electron micrograph (SEM) and differential scanning calorimetric (DSC) techniques were employed to characterize the morphology and crosslinking of PVA fibers. It was found that the primary factor which affected the crosslinking density was the content of chemical crosslinking agent.     

Thermal degradation and cyclodepolymerization of poly(ethylene terephthalate-co-isophthalate)s

The thermal degradation of poly(ethylene terephthalate-co-isophthalate)s (PETIs) is investigated by using isothermal thermogravimetric analysis at the temperature range of 280–310°C. The degradation rate of PETIs is increased as the mole ratio of ethylene isophthaloyl (EI) units in PETIs increases. The activation energies for the thermal degradation of poly(ethylene terephthalate), PETI(5/5), and poly(ethylene isophthalate) are 33.4, 16.6, and 8.9 kcal/mole, respectively. The degradation rate of PETIs is influenced by their volatile cyclic oligomer components formed during the polymerization and the thermal degradation. It is simulated by the rotational isomeric state model that the content of cyclic dimer in PETIs, which is the most volatile cyclic oligomer component, increases with the EI units in PETIs.     

Removal of benzidine-based azo dye from aqueous solution using amide and amine-functionalized poly(ethylene terephthalate) fibers

In this study, amide and amine groups bound to poly(ethylene terephthalate) fibers are used to remove the colored toxic Congo red dye from aqueous solution. The effects of process variables like pH, contact time, graft yield, and initial dye concentration on the adsorption were investigated. The maximum adsorption of Congo red to amide and amine groups was observed at pH 3 and 5 respectively. Equilibrium was attained at approximately 60 min for the amine group. The adsorption capacity of amine group on the poly(ethylene terephthalate) fiber was 46.5 mg g⁻¹ at 25 °C, which was higher than that of the amide group on the poly(ethylene terephthalate) fiber. Desorption was done using 0.1 M NH₃, and recovery was measured at 58.2 %. The used adsorbent was regenerated and recycled six times. The results showed that the amine-functionalized fiber could be considered as potential adsorbents for removal of Congo red from aqueous solution.     

New biopolymer nanocomposites based on epoxidized soybean oil plasticized poly(lactic acid)/fatty nitrogen compounds modified clay: Preparation and characterization

Biodegradable polymers, such as poly(lactic acid) (PLA) have attracted a lot of attention in the scientific community recently due to a rapid growth of intensive interest in the global environment for alternatives to petroleum-based polymeric materials. Fatty nitrogen compounds (FNCs), fatty amides (FA), fatty hydroxamic acids (FHA), and carbonyl difatty amides (CDFA), which were synthesized from vegetable oils, were used as one of organic compounds to modify natural clay (sodium montmorillonite). The clay modification was carried out by stirring the clay particles in an aqueous solution of FA, FHA, and CDFA, by which the clay layer thickness increased from 1.23 to 2.61, 2.84 and 3.19 nm, respectively. The modified clay was then used in the preparation of the PLA/epoxidized soybean oil (ESO) blend nanocomposites. They were prepared by incorporating 2% of CDFA-MMT and 3% of both FA-MMT and FHA-MMT. The interaction of the modifier in the clay layer was characterized by X-ray diffraction (XRD), and Fourier transform infrared (FTIR). Elemental analysis was used to estimate the presence of FNCs in the clay. The nanocomposites were synthesized by solution casting of the modified clay and a PLA/ESO blend at the weight ratio of 80/20, which has the highest elongation at break. The XRD and transmission electron microscopy (TEM) results confirmed the production of nanocomposites. PLA/ESO modified clay nanocomposites show higher thermal stability and significant improvement of mechanical properties in comparison with those of the PLA/ESO blend. The novelty of this study is use of FNCs which reduces the dependence on petroleum-based surfactants.     

Synthesis,structure, and thermal property of poly(trimethylene terephthalate-<Emphasis Type="Italic">co</Emphasis>-trimethylene 2,6-naphthalate) copolymers

Poly(trimethylene terephthalate-co-trimethylene 2,6-naphthalate)s (P(TT-co-TN)s) with various copolymer composition were synthesized, and their chain structure, thermal property and crystalline structure were investigated by using¹H-NMR spectroscopy, differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXD), respectively. It was found from sequence analysis that all the P(TT-co-TN) copolymers synthesized have a statistical random distribution of TT and TN units. It was also observed from DSC thermograms that the glass transition temperature increases linearly with increasing the TN comonomer content, whereas the melting temperature of copolymer decreases with increasing the corresponding comonomer content in respective PTT- and PTN-based copolymer, showing pseudo-eutectic melting behavior. All the samples melt-crystallized isothermally except for P(TT-co-66 mol % TN) exhibit multiple melting endotherms and clear X-ray diffraction patterns. The multiple melting behavior originates from the dual lamellar population and/or the melting-recrystallization-remelting. The X-ray diffraction patterns are largely divided into two classes depending on the copolymer composition, i.e., PTT and PTNβ-form diffraction patterns, without exhibiting cocrystallization.     

Coloration of poly(lactic acid) with disperse dyes. 1. Comparison to poly(ethylene terephthalate) of dyeability, shade and fastness

The dyeability of poly(lactic acid) [PLA] with a range of commercial disperse dye was examined and compared to that of poly(ethylene terephthalate) [PET] in addition to the colour and fastness of the resultant dyeings. A screening exercise in which twenty dyes of differing energy types and chemical classes were applied to PLA revealed a substantial variation between the dyes in terms of dye uptake (12–88 % at 4 %o.w.f.). Nine dyes exhausted above 70 % and were selected for further study, which involved comparison of shade and fastness of PLA dyeings with those of the corresponding PET dyeings. Differences in shade depended on hue while wet fastness of each of the PLA dyeings was either the same or 0.5–1.0 point lower than its PET counterpart. In all but one case, dye photostability in PLA was found to be very similar to that in PET. Dye build-up profiles on PLA were also investigated and from these results mixtures of compatible dyes identified.     

Processing and characterization of liquid crystalline copoly-(ethylene terephthalate-co-2(3)-chloro-1,4-phenylene terephthalate)/polycarbonate blends

Liquid crystalline (LC) poly(ethylene terephthalate-co-2(3)-chloro-1,4-phenylene terephthalate) (50/50, mole/mole) [PECPT] was synthesized and blended with polycarbonate (PC). LC properties of PECPT and thermal, morphological, and rheological behaviors of the PECPT/PC blend were studied. PECPT showed the nematic LC phase and much longer relaxation time than poly(ethylene terephthalate) (PET). The apparent melt viscosity of PECPT was one third of that of PET. An abrupt torque change was observed during the blending process due to the orientation of LC domains. For the blends containing 10∼30 wt% of PECPT, the complex viscosities were higher than that of PC. As PECPT content increases above 40 wt%, shear thinning was observed. The lowest complex viscosity was obtained at 40∼50 wt%. Transesterification of PECPT and PC was confirmed by the selective chemical degradation of carbonate groups in PC.     

Fine structure and physical properties of poly(buthylene terephthalate) sheets prepared by roller drawing method

Poly(butylene terephthalate) sheets were prepared by roller-drawing method with various draw ratio. The drawing temperature is 100 °C and draw ratios were varied 2, 2.5, 3, 3.5 and 4. The effect of draw ratio on the crystal structure, the molecular orientation, dynamic viscoelastic properties, sonic modulus and tensile properties of the roller-drawn PBT sheets were investigated. In WAXD results, with increasing of the draw ratio, (010) and (100) planes of preferred orientation have the strongest intensity on the equator. In the meridional scans, it was confirmed that α and β crystal co-existed in the roller drawn PBT sheets with various draw ratio. Uniaxially roller-drawn PBT sheets clearly increased orientation along the stretched direction at high draw ratio. And the four-methylene groups of PBT orient along the surface of the sheet. The mechanical properties of PBT sheets were improved by orientation-induced crystallization during roller drawing process at 100 °C.     

Interchange reaction kinetics and sequence distribution of liquid crystalline poly(ethylene terephthalate-co-2(3)-chloro-1,4-phenylene terephthalate)

Liquid crystalline (LC) poly(ethylene terephthalate-co-2(3)-chloro-1,4-phenylene terephthalate) [copoly(ET/CPT)] was prepared using poly(ethylene terephthalate) (PET) as a flexible spacer, terephthalic acid (TPA), and chlorohydroquinone diacetate (CHQDA). All reactions involved in the copolymerization were investigated using some model compounds: TPA was used for acidolysis, diphenylethyl terephthalate (DPET) for interchange reaction between PET chains, and di-o-chlorophenyl terephthalate (DOCT) and di-m-chlorophenyl terephthalate (DMCT) for interchange reaction between PET and rigid rodlike segments. Activation energies obtained for the acidolysis of PET with TPA and for interchange reaction of PET with DPET, DOCT, and DMCT were 19.8 kcal/mole, 26.5 kcal/mole, 60.2 kcal/mole, and 45.9 kcal/mole, respectively. This result supports that the copolymerization proceeds through the acidolysis of PET with TPA first and subsequent polycondensation between carboxyl end group and CHQDA or acetyl end group, which is formed from the reaction of CHQDA and TPA. Also, it was found that ester-interchange reaction can be influenced by the steric hindrance. Copoly(ET/CPT)s obtained had ethylene acetate end groups formed from acetic acid and hydroxy ethylene end groups and showed almost the random sequence distribution for all compositions.     

Thermal decomposition kinetics of copolymers derived from<Emphasis Type="Italic">p</Emphasis>-dioxanone,L-lactide and poly(ethylene glycol)

The kinetic parameters, including the activation energyE, the reaction ordern, and the pre-exponential factorZ, of the degradation of the copolymers based on the poly(L-lactide) (PLLA) or poly(p-dioxanone-co-L-lactide) (PDO/PLLA) and diol-terminated poly(ethylene glycol) (PEG) segments have been evaluated by the single heating methods of Friedman and Freeman-Carroll. The experimental results showed that copolymers exhibited two degradation steps under nitrogen that can be ascribed to PLLA or PDO/PLLA and PEG segments, respectively. However, copolymers exhibited almost single degradation step in air. Although the values of initial decomposition temperature were scattered, copolymers showed the lower maximum weight loss rate and degradation-activation energy in air than in nitrogen whereas the higher value of temperature at the maximum rate of weight loss was observed in air.     

Properties of thermoplastic starch from cassava bagasse and cassava starch and their blends with poly (lactic acid)

Cassava bagasse is an inexpensive and broadly available waste byproduct from cassava starch production. It contains roughly 50% cassava starch along with mostly fiber and could be a valuable feedstock for various bioproducts. Cassava bagasse and cassava starch were used in this study to make fiber-reinforced thermoplastic starch (TPS_B and TPS_I, respectively). In addition, blends of poly (lactic acid) and TPS_I (20%) and TPS_B (5, 10, 15, 20%) were prepared as a means of producing low cost composite materials with good performance. The TPS and PLA blends were prepared by extrusion and their morphological, mechanical, spectral, and thermal properties were evaluated. The results showed the feasibility of obtaining thermoplastic starches from cassava bagasse. The presence of fiber in the bagasse acted as reinforcement in the TPS matrix and increased the maximum tensile strength (0.60 MPa) and the tensile modulus (41.6 MPa) compared to cassava starch TPS (0.40 and 2.04 MPa, respectively). As expected, blending TPS with PLA reduced the tensile strength (55.4 MPa) and modulus (2.4 GPa) of neat PLA. At higher TPS_B content (20%) the maximum strength (19.9 MPa) and tensile modulus (1.7 GPa) were reduced about 64% and 32%, respectively, compared to the PLA matrix. In comparison, the tensile strength (16.7) and modulus (1.2 GPa) of PLA blends made with TPS_I were reduced 70% and 51% respectively. The fiber from the cassava bagasse was considered a filler since no increase in tensile strength of PLA/TPS blends was observed. The TPS_I (33.1%) had higher elongation to break compared to both TPS_B (4.9%) and PLA (2.6%). The elongation to break increased from 2.6% to 14.5% by blending TPS_I with PLA. In contrast, elongation to break decreased slightly by blending TPS_B with PLA. Thermal analysis indicated there was some low level of interaction between PLA and TPS. In PLA/TPS_B blends, the TPS_B increased the crystallinity of the PLA component compared to neat PLA. The fiber component of TPS_B appeared to have a nucleating effect favoring PLA crystallization.