Showing papers on "Polycarbonate published in 2009"

Surface modifications of polycarbonate (PC) and acrylonitrile butadiene styrene (ABS) copolymer by treatment with atmospheric plasma

Abstract: Two engineering thermoplastic polymers (polycarbonate, PC, and acrylonitrile butadiene styrene copolymer, ABS) were treated with atmospheric plasma torch using different treatment rates (1, 5 and 10 m/min). The modifications produced by the treatment were analysed by contact angle measurements, XPS, SEM and ATR-IR spectroscopy. Particular emphasis was placed on the ageing (up to 30 days) after atmospheric plasma treatment on both polymers. The slower the atmospheric plasma treatment, the greater the wettability of the treated polymers. The decrease in water contact angle was mainly ascribed to a significant increase in oxygen content due to the formation of carboxylic and hydroxyl groups and a decrease in the carbon content on the polymer surfaces. After natural ageing, there was an increase in the water contact angle, although the values of the untreated polymer surface were never reached.

Structure-Mechanical Property Relationships for Poly(carbonate urethane) Elastomers with Novel Soft Segments

Abstract: A series of eight aliphatic polycarbonate (PC) glycols with various methylene numbers (HO−[(CH2)mOC(═O)O]n−(CH2)m−OH, m = 3, 4, 5, 6, 7, 8, 9, and 10) were employed as a soft segment for a synthesi...

Chemical recycling of polymers from Waste Electric and Electronic Equipment

Abstract: This research is focused on the recycling of three types of polymers, namely polycarbonate (PC), poly(acrylonitrile-butadiene-styrene) (PABS), and polystyrene (PS) from Waste Electric and Electronic Equipment (WEEE). Initially, the chemical structure of each polymeric material in a variety of WEEE was identified by Fourier Transform Infra Red (FTIR) spectroscopy and Differential Scanning Calorimetry (DSC). The potential recycling of these polymers from these wastes was examined by employing two different approaches, the dissolution/reprecipitation method and the more challenging technique of pyrolysis. During the first, the polymer is separated and recycled through a solvent/non-solvent system. It is a simple and economic technique leading to high recovery of pure polymer. Both, model polymers and plastic parts from WEEEs were studied and optimum experimental conditions, including dissolution temperature and time, polymer concentration and type of solvent were proposed to achieve significant recovery of the polymer (>90 wt %). Furthermore, pyrolysis of waste Compact Disks (CD) was investigated and compared with model poly(bisphenol A carbonate) (PC) through a laboratory-scale fixed bed reactor. The appropriate pyrolysis temperature was selected after measuring the thermal degradation of model PC by Thermogravimetric analysis (TGA). A large amount of oil was measured, together with a smaller amount of gaseous product, leaving also a solid residue. For both samples, the gaseous fraction consisted mainly of CO2 and CO whereas in the liquid fraction a large amount of different phenolic compounds, including the monomer bisphenol A, was measured. It seems that recycling of used CDs by pyrolysis is a very promising technique having the potential of producing useful high-value chemicals, which may find applications in the petrochemical industry. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Novel coordination complexes and process of producing polycarbonate by copolymerization of carbon dioxide and epoxide using the same as catalyst

Abstract: Provided are a complex prepared from ammonium salt-containing ligands and having such an equilibrium structural formula that the metal center takes a negative charge of 2 or higher, and a method for preparing polycarbonate via copolymerization of an epoxide compound and carbon dioxide using the complex as a catalyst. When the complex is used as a catalyst for copolymerizing an epoxide compound and carbon dioxide, it shows high activity and high selectivity and provides high-molecular weight polycarbonate, and thus easily applicable to commercial processes. In addition, after forming polycarbonate via carbon dioxide/epoxide copolymerization using the complex as a catalyst, the catalyst may be separately recovered from the copolymer.

Method of hydrolytically stable bonding of elastomers to substrates

Abstract: Active devices such as pumps and mixers have been fabricated in plastic-PDMS hybrid devices By utilizing functionalized bis-silane primers, bond strength between Polycarbonate or PMMA and PDMS improved in dry and aqueous environments Plastic-primer-PDMS layers exposed to acid and base solutions at 70° C for 2 hours showed no signs of delamination at 30 psi for pH −1 to 15 and 60 psi for pH 0 to 15 A peristaltic pump fabricated in polycarbonate achieved consistent flow rates up to peristaltic cycle frequencies of 10 Hz in water, 1OM HCl, and 1OM NaOH solutions

Kinetics of Polycarbonate Glycolysis in Ethylene Glycol

Abstract: Depolymerization of polycarbonate waste by glycolysis using ethylene glycol without catalyst was explored in order to get the monomer bisphenol A (BPA). The depolymerized products were identified by GC/MS and FTIR spectroscopy. The effects of operation variables such as reaction time, reaction temperature, ethylene glycol/polycarbonate (EG/PC) weight ratio, and the kinetics of glycolysis were studied. A maximum yield of BPA of 95.6% was achieved at a reaction temperature of 220 °C for 85 min with an EG/PC weight ratio 4. It was found that the depolymerization reaction has two different activation energies, indicating that the reaction occurs in series. A new model was proposed to explain the depolymerization reaction which consists of a series of reactions: random scission from high molecular weight PC to its solid oligomer, dissolution from the solid oligomer to liquid oligomer, and homogeneous degradation from the liquid oligomer to its monomer, BPA. The activation energies were found to be 98.9 kJ/mol ...

Polycarbonate resin composition with improved transparency and scratch-resistance

Abstract: A polycarbonate resin composition can have improved transparency and scratch resistance of the present invention and comprises about 10 to about 99% by weight of polycarbonate resin (A); and about 1 to about 90% by weight of acrylic copolymer with ultra-low molecular weight and high refractive index (B). The resin composition of the present invention can further comprise acrylic resin (C). The acrylic copolymer with ultra-low molecular weight and high refractive index (B) can have a refractive index of about 1.495 to about 1.590 and a weight average molecular weight of about 3,000 to about 40,000 g/mol.

Polycarbonate resin composition

Abstract: PROBLEM TO BE SOLVED: To provide a polycarbonate resin composition which has excellent appearance with no pearly gloss and of which the appearance and the fluidity are improved without damaging the impact resistance by improving compatibility between a polycarbonate and a polylactic acid. SOLUTION: The polycarbonate resin composition comprises: the polycarbonate (A); the polylactic acid (B); and a block copolymer (C) having a polyhydroxy carboxylic acid structural unit (I) and a polyester structural unit (II) obtained by esterification of a dicarboxylic acid with a diol. COPYRIGHT: (C)2009,JPO&INPIT

Fouling and Degradation of Polycarbonate in Seawater: Field and Lab Studies

Abstract: Biofouling and ensuing microbial mediated degradation of Bisphenol A polycarbonate was studied by immersing the samples in sea water of Bay of Bengal (Chennai, India) for 3 months and also under controlled laboratory conditions with marine mixed microbial consortia for 12 months. A 9% weight loss in the sample was observed after 1 year of incubation under in vitro laboratory conditions. A 5% reduction in number average molecular weight and an additional oligomer with a molecular weight of 930 was observed in the same sample. Contact angle decreased by 11% indicating an increase in the surface hydrophilicity. The specific heat decreased by 44% and glass transition temperature decreased by 3 °C with respect to the control indicating chain scission. Formation of new hydroxyl groups and cleavage of carbonate bonds in polycarbonate suggested biodegradation. About 9 μg mL−1 of Bisphenol A, a monomer of polycarbonate, as well as its oxidized products were detected in the supernatant. The nature of degradation in field and in vitro was different. It was predominantly oxidation in the former and hydrolysis in the later environment. A strain exhibiting hydrolase activity was isolated at the end of the 12 months from the in vitro mixed consortia and was identified, based on biochemical and 16S rDNA tests, as Pseudomonas sp. BP2 (GenBank accession no. EU920674).

Cinnamate‐functionalized poly(ester‐carbonate): Synthesis and its UV irradiation‐induced photo‐crosslinking

Abstract: A functionalized. cyclic carbonate monomer containing a cinnamate moiety, 5-methyl-5-cinnamoyloxymethyl-1,3-dioxan-2-one (MC), was prepared for the first time with 1,1,1-tri(hydroxymethyl) ethane as a starting material. Subsequent polymerization of the new cyclic carbonate and its copolymerization with L-lactide (LA) were successfully performed with diethyl zinc (ZnEt2) as initiator/catalyst. NMR was used for microstructure identification of the obtained monomer and copolymers. Differential scanning calorimetry (DSC) was used to characterize the functionalized poly(ester-carbonate). The results indicated that the copolymers displayed a single glass transition temperature (T-g) and the T, decreased with increasing carbonate content and followed the Fox equation, indicative of a random microstructure of the copolymer. The photo-crosslinking of the cinnamate-carrying copolymer was also demonstrated.

Experimental and theoretical studies of agglomeration effects in multi-walled carbon nanotube-polycarbonate melts

Abstract: In this study we report on morphological and rheological characterization of multi-walled carbon nanotube (MWNT)-polycarbonate composites produced by injection molding. The main focus is to carry out nonlinear viscoelastic experiments that allow following the structural rearrangements of carbon nanotubes in the polycarbonate melt. Small angle X-ray scattering reveals only a slight orientation of MWNTs in the as-received samples, i.e. after application of extremely high shear rates. Thus, the main structural effect observed during the stress growth experiment is the breakage of MWNT agglomerates. To study this effect in detail a flocculation experiment, in which the sample undergoes oscillatory deforma- tion first at a small strain amplitude in the linear regime succeeded by higher amplitudes in the nonlinear regime, has been carried out. The agglomeration process manifests itself in an increase of the storage and loss moduli in the linear regime, whereas the deagglomeration process does vice versa. The corresponding effects can be described in the frame of a super- position approach that takes into account the stress contribution of the polycarbonate matrix, the hydrodynamic reinforce- ment due to embedded nanotubes and the viscoelastic stress due to the presence of a MWNT-network.

Polycarbonate resin composition with improved scratch resistance and melt flow index

Abstract: A polycarbonate resin composition of the present invention comprises about 40 to about 99% by weight of a polycarbonate resin (A), about 1 to about 60% by weight of an acrylic copolymer (B) having a high refractive index and a flexible structure, and about 0 to about 60% by weight of acrylic resin (C). A polycarbonate resin composition of the present invention can have excellent transparency and scratch resistance without requiring extra compatibilizers by including an acrylic copolymer having a high refractive index and a flexible structure with the polycarbonate resin.

Synthesis of linear aliphatic polycarbonate macroglycols using dimethylcarbonate

Abstract: A series of linear aliphatic polycarbonate polyols were synthesized using dimethylcarbonate and a linear alkane diol or specific combinations of linear alkane diols. Polyol synthesis was carried out in a two-stage process using dimethylcarbonate and a linear alkane diol to prepare a series of homopolymer polycarbonate polyols. Polyol grades were characterized using Fourier transform infrared spectroscopy, gel permeation chromatography, and differential scanning calorimetery techniques. Suitable reaction conditions were developed to yield polycarbonate polyols of number average molecular weight between 700 and 1700. The crystallinity of the polycarbonate polyols was shown to reduce as the molecular weight of the alkane diols used in the polycarbonate synthesis was increased. These polymers offer the potential for use in the synthesis of ether free polyurethane elastomers for biomedical applications. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Morphology, miscibility and mechanical properties of PMMA/PC blends

Abstract: This study deals with some results on morphology, miscibility and mechanical properties for polymethyl methacrylate/polycarbonate (PMMA/PC) polymer blends prepared by solution casting method at different concentration between 0 and 100 wt%. Dynamic storage modulus and tan δ were measured in a temperature range from 30 to 180°C using dynamical mechanical analyzer (DMA). The value of the storage modulus was found to increase with the addition of the PC in the matrix. Transition temperature of pure PMMA and pure PC is found to be 83.8 and 150°C, respectively. The result shows that the two polymers are miscible for whole concentration of PC in PMMA. The distribution of the phases in the blends was studied through scanning electron microscopy (SEM). Also the mechanical properties like elongation at break and fracture energy of the PMMA/PC blends increase with the increase in concentration of PC in PMMA.

Polycarbonate resin, polycarbonate resin composition, optical film, and polycarbonate resin molded article

Abstract: Disclosed is a polycarbonate resin which contains a constituent unit derived from a specific dihydroxy compound, and has excellent heat resistance and transparency. Also disclosed is a composition containing the polycarbonate resin. The polycarbonate resin contains at least a constituent unit derived from a dihydroxy compound having a bond structure represented by structural formula (1). The polycarbonate resin is characterized in that the ratio of (A) the number of end groups represented by structural formula (2) relative to (B) the total number of end groups, namely (A)/(B), is not less than 20%. (In this connection, a hydrogen atom is not bonded to the oxygen atom in structural formula (1).)

Improvement of the properties of PC/LCP blends in the presence of carbon nanotubes

Abstract: Polycarbonate (PC)/liquid crystalline polymer (LCP)/Multiwall carbon nanotube (MWNTs) nanocomposites containing as-received and modified (COOH-MWNT) carbon nanotubes were prepared through melt process in extruder and then compression molded. The chemical modification of MWCNT enhances the compatibility as well as miscibility between Polycarbonate and LCP in the concerned composites. Incorporation of functionalized MWCNTs improves the thermal, mechanical dynamic mechanical and electrical properties of the composites. Storage modulus and glass transition temperature increases in a remarkable fashion due to the enhanced interfacial adhesion between the PC/LCP/COOH-MWCNT. Field emission microscopy (FESEM) and HRTEM exhibit LCP fibrillation and fine dispersion of COOH-MWCNT throughout the matrix highlighting the miscibility between LCP and PC matrix.

Characterization of twin-screw-extruder-compounded polycarbonate nanoclay composites

Abstract: Polycarbonate nanocomposites were prepared by melt processing from two surface-modified montmorillonite organoclays. The intercalation spacing and degree of the dispersion were characterized with wide-angle X-ray diffraction and transmission electron microscopy, respectively. The polycarbonate nancomposites showed rather good dispersion of nanoclay, with a mixture of exfoliated, intercalated, and confined morphology. The effect of nanoclay on the mechanical response of specimens subjected to tensile and impact loading was investigated. Results demonstrated that nanocomposites based on nanoclay possess increased Young's modulus and yield strength. However, their ductility upon tensile loading is significantly affected. A transition from ductile to brittle deformation occurs at studied clay loadings. Notched impact strength experiments supported this, showing that impact strength decreases significantly as nanoclay content increases from 1 to 5 wt%, regardless how the nanoclay surface was modified. Thermal analysis demonstrated that addition of nanoclay leads to decreased thermal stability of polycarbonate suggesting, enhanced dynamics of polymer chains. Finally, the tribological properties of selected specimens were evaluated using a pin-on-disc, and the effect of nanoclay fillers on tribological properties is discussed.

Rheology, Morphology, Mechanical Properties and Free Volume of Poly(trimethylene terephthalate)/Polycarbonate Blends

Abstract: The phase morphology, rheology, mechanical properties, and free volume of poly(trimethylene terephthalate)/polycarbonate (PTT/PC) blends have been investigated as a function of composition. The morphology indicated a two-phase structure, and the blends showed co continuous phase morphology between 30−60 wt % of poly carbonate. Due to the high viscosity of PC, PTT is more finely dispersed in the PC matrix than PC in the PTT matrix. The rheological measurements of the blends revealed that the complex viscosity increased with increase in PC content. Relatively low interfacial tension values of the blends determined using Palierne and Choi−Schowalter methods indicated that there is considerable interaction between the blend components (PTT and PC) due to the transesterification reactions. A random copolyester formed as a result of the transesterification acted as a compatibilizer in the initial stages of reactions which is the main factor for the change in miscibility. The phase morphology and the interfacial...

A study on reaction-induced miscibility of poly(trimethylene terephthalate)/polycarbonate blends.

Abstract: The effect of annealing on the miscibility and phase behavior of Sorona {poly(trimethylene terephthalate), PTT} and bisphenol A polycarbonate (PC) blends was examined. These blends exhibited hetero...

Mechanical, Morphological and Thermal Properties of Polycarbonate/SEBS-G-MA/Montmorillonite Nanocomposites

Abstract: Nanocomposites based on polycarbonate (PC) containing sodium montmorillonite (NaMMT) and maleic anhydride grafted styrene-ethylene/butylene-styrene (SEBS-g-MA) were prepared by melt compounding method followed by injection molding X-ray diffraction (XRD) and transmission electron microscopy (TEM) results revealed the formation of intercalated nanocomposites Incorporation of SEBS-g-MA into the PC/MMT nanocomposites enhanced ductility and impact strength but slightly reduced tensile strength and stiffness The glass transition temperature (T g – detected from DMTA) and onset temperature (T onset – detected from TGA) of the PC nanocomposites was increased in the presence of SEBS-g-MA For this PC/NaMMT system, SEBS-g-MA could act as an effective toughening agent

Plasma functionalization of multiwalled carbon nanotube bucky papers and the effect on properties of melt-mixed composites with polycarbonate.

Abstract: Multiwalled carbon nanotubes in the form of bucky papers were modified using Ar/O(2) plasma and thereafter melt-mixed into polycarbonate. The effect of plasma modification on the nanotubes was followed by XPS, indicating the formation of carboxylic or ester groups at the nanotube surfaces. In the melt-mixed nanocomposites, the modified nanotubes exhibited a better macrodispersion and better phase adhesion to the matrix as evidenced by morphological investigations. The electrical percolation threshold was not altered and occurred below 0.5 wt.-% nanotubes. The mechanical properties were improved by having higher values of stress at yield, stress beyond the yield point, and strain at break illustrating the effect of both better dispersion and enhanced phase adhesion.