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The effects of triethyl citrate (TEC) on the viscoelastic properties of a copolycarbonate comprising isosorbide and 1,4-cyclohexanedimethanol (ISB-PC) were studied in both the molten and solid states. TEC acted as an antiplasticizer for ISB-PC and increased its modulus in the glassy state, as demonstrated in blends comprising 5 and 10 wt% TEC. Because antiplasticization reduces the free volume fraction, the water content of the copolycarbonate films, which is known to affect various properties, decreased following the addition of TEC. Furthermore, TEC greatly decreased the zero-shear viscosity. The experimental values were much lower than those predicted by the Berry–Fox formula. In other words, a small amount of TEC greatly enhances the flowability of ISB-PC. [ABSTRACT FROM AUTHOR]

High impact resistance transparent materials are still a challenging task in respect of its strategic applications. Increasing the impact resistance of the polycarbonates have always been the focus of the material manufacturers for years. This study provides an effective solution to the bird strikes on aircraft by utilizing solvent vapor bonding to make the polycarbonate laminates that can be used in wind- shields. Dichloromethane has been proved to be the best solvent for solvent vapor bonding process from Lap Shear Tensile tests as the bond made is of high strength. The effective bonding in the solvent vapor bonded is much greater than the bonding in normal windshields greatly increasing the impact resistance of windshields by fifty percent along with the retention of transparency in the material. The toughness of the material after solvent vapor bonding is increased by fifteen times. The entire process of making the polycarbonate laminates for aviation and defence applications has been discussed in great depth. [ABSTRACT FROM AUTHOR]

Coarse-grained molecular dynamics simulation of polycarbonate is utilized to investigate the relationship between molecular structure (i.e., polydispersity and molecular spatial distribution) and strain-hardening and fracture behavior of polycarbonate. We find that strain-hardening modulus and chain extensibility, which are the constitutive parameters of the Eindhoven Glassy Polymer model are highly affected by spatial distribution but are insensitive to polydispersity. This is attributed to the higher rate of nonaffine deformation in the structure with a high radius of gyration. On the other hand, maximum stress at fracture is highly influenced by both spatial distribution and polydispersity due to the ability to sustain entanglements at larger strain. We suggest the phenomenological expression of maximum stress as a function of the radius of gyration, the number of entanglements, and polydispersity. [ABSTRACT FROM AUTHOR]

The deformation behavior (i.e., yield strength) of engineering polymers is known to be strongly dependent on the strain rate. Among these polymers, polycarbonate (PC) exhibits excellent impact fracture resistance, but the deformation mechanism of molecular chains needs to be elucidated. The molecular deformation mechanisms occurring during atomic force microscopy (AFM), nanoindentation experiments, and the laser-induced particle impact test (LIPIT) are investigated using a coarse-grained molecular dynamics (CG-MD) simulation. In these methods, elastoplastic deformation is locally induced on the sample surface and the AFM experiment is conducted at a relatively lower loading rate (as the quasi-static test), while LIPIT is conducted at a higher loading rate (as the impact test). To investigate the deformation mechanism during these experiments, variations in the potential energy associated with molecular deformation are evaluated by CG-MD simulations. For the AFM experiment, the bending mode of the molecular chain plays a critical role in the onset of yielding. Our CG-MD computation accurately reproduces the experimental indentation force–displacement curves. Next, LIPIT with high-speed particle collisions is conducted, leading to local elastoplastic deformation at a high strain rate. The yield strength of LIPIT becomes significantly greater (10 times larger) than that of the quasi-static test. From the CG-MD simulation, the molecular deformation mechanism during LIPIT revealed that the bond stretching and bending angle of the molecular chain are critical for yield strength under local loading (indentation and particle impact). In other words, yield strength at a high loading rate increases significantly as a result of the local deformation acting on the bond stretching of the molecular chain. [ABSTRACT FROM AUTHOR]

In this study, iso-sorbitol type polycarbonate (PIC) was synthesized with isosorbide (ISB) and diphenyl carbonate (DPC) as reactive monomers. The flexible co-monomers 1,4-butanediol (BDO) and 1,4-cyclohexane dimethanol (CHDM) were introduced to improve its property. Then, two iso-sorbitol type polycarbonate copolymers were obtained: Isosorbitol type polycarbonate copolymer (PIBC) containing 1,4-butanediol (BDO) and isosorbitol type polycarbonate copolymer (PICC) containing 1,4-cyclohexane dimethanol (CHDM). The results of 1H-NMR and FT-IR demonstrated that the structures of PC, PIC, PIBC, and PICC synthesized by the experiment were consistent with the theoretical structures. The results of the characteristic viscosity test suggested that the copolymer with high relative molecular weight was successfully prepared. The results of DSC and TGA revealed that the introduction of a flexible copolymer increased the relative molecular weight of the copolymer, decreased the glass transition temperature, and exerted little effect on the thermal stability of the copolymer. The mechanical properties test results unveiled that PICC has good mechanical properties. Owing to its excellent mechanical and thermal properties, there is a broad application prospect of the PICC as a green polycarbonate material. [ABSTRACT FROM AUTHOR]

Attaining nanocomposites having high mechanical and electrical properties simultaneously via carbon based nanomaterials remains exciting as carbon nanomaterial have a pattern of formation of random dispersive networks in polymeric nanocomposites. Here, polycarbonate/ethylene methyl acrylate blend (PC/EMA) nanocomposites were fabricated using graphene to explore their effect on electrical, mechanical, and electromagnetic interference (EMI) shielding properties. The mechanical properties of the nanocomposites are improved by enhancing the graphene content. EMI shielding properties of graphene based composites were calculated in X band. The fabricated PC/EMA-graphene nanocomposites showed an EMI shielding of -51 dB for 15 phr graphene loading. Thus, the excellent EMI shielding performance and sensitive response combination make the nanocomposites promising material for many potential applications in next-generation electronics. [ABSTRACT FROM AUTHOR]

Poly (l-lactic acid) (PLLA) and polycarbonate (PCL) grafted Monoamino-Polyhedral oligomeric silsesquioxane (POSS-NH2) (POSS-PLLA and POSS-PCL) by ring-opening polymerization of L-lactide (L-LA) and caprolactone (ε-CL) from POSS-NH2 were obtained in this work. The fourier transform infrared spectrometer (FTIR) results show that the stretching vibration peaks of -C(O)-NH- of POSS-PLLA and POSS-PCL appears at 1650 cm−1 and 1645 cm−1. The crystal diffraction peaks of POSS-PLLA at 22°, 16.7° and 19° are same as the peak positions of PLLA; POSS-PCL at 21.7° 23.7° are same as the peak positions of PCL by X-Ray diffraction (XRD). Both FTIR and XRD results indicate that the grafted products are synthesized successfully. Then, the different contents of POSS-PLLA, POSS-PCL and purchased POSS-polyethylene glycol (POSS-PEG) were blended with PLLA/Poly (d-lactic acid) (PDLA) (with the mass ratio of 1:1) to prepare ternary blends with different contents of polymer grafted POSS. The effects of POSS-PLLA, POSS-PCL and POSS-PEG on the crystallization behavior of PLLA/PDLA were investigated. The results show that compared with POSS-PCL and POSS-PLLA, POSS-PEG enhances the crystallization ability of PLLA/PDLA, and promotes the formation of stereocomplex (SC); on the contrary, POSS-PCL and POSS-PLLA inhibit the formation of SC. [ABSTRACT FROM AUTHOR]

The brittle-to-ductile transition is investigated in polycarbonate (PC) after different types of thermomechanical treatment. In addition to the stress versus strain curves in uniaxial stretching to fracture of the original, preheated, shape recovered and high temperature pre-stretched samples, photoelasticity is applied to reveal the internal stress field in the fracture samples and high temperature pre-stretched samples. The change in microstructure after pre-deformation is concluded to be the reason behind the brittle-to-ductile transition. However, the type of subsequent loading to fracture is also important to determine if there is any transition. The magnitude of pre-deformation, the temperature of pre-deformation and the maximum deformation capability of the original material are three major parameters that affect the significance of brittle-to-ductile transition. [ABSTRACT FROM AUTHOR]

Copolycarbonate was synthesized by melt transesterification method, using diphenyl carbonate, isosorbide and 1,4-cyclohexanedimethanol (CHDM) as raw materials. The copolymer composition and random structure of the copolymer were determined by Fourier transform infrared and 1H NMR analysis. The DSC and TGA analysis showed that CHDM was introduced into the isosorbide polycarbonate chain, which effectively lowered the glass transition temperature of the polymer without lowering the thermal decomposition temperature. The glass transition temperature of the copolymer can be controlled by the addition amount of CHDM, and its processing performance can be improved. In addition, the introduction of CHDM did not reduce the high light transmittance (> 91.5%) of isosorbide polycarbonate. With the gradual increase of the amount of CHDM added, the refractive index of the copolymer decreases slightly. When the CHDM content is 30 mol%, the glass transition temperature (Tg)of the copolymer is 132.2 °C, the thermal decomposition temperature is > 350 °C, the refractive index is 1.4960, the Abbe number is 51, and the transmittance is 91.6%, and the haze is 1.07%. [ABSTRACT FROM AUTHOR]

Using a phase inversion process, composite membranes were fabricated using polycarbonate (PC) recovered from waste compact discs (CDs), polysulfone (PSf) and chitin nanowhisker (CNW). The effect of recovered PC (rPC) and PSf ratios on membrane properties were studied. Differential scanning calorimetry (DSC) and the clarity of the homogenous blend solutions revealed that rPC and PSf were partially miscible. rPC and high molecular weight PC (hPC) were degraded by alkaline media but increments of PSf content improved the alkaline resistance of the blend membranes. The tensile properties of an rPC/PSf membrane with a weight ratio of 50/50 were comparable to those of hPC. The effects on the optimized blend membrane of a fixed content of Pluronic F127 (Plu127), as a pore forming agent, and various loadings of CNW were evaluated. CNW in the casting solution improved the tensile properties, permeability and hydrophilicity of the obtained composite membranes. A loading of 6 wt% CNW produced a good pure water flux (262.6 L/m2h) and the highest BSA rejection (94.4%) and flux recovery ratio (94.6%). Moreover, antifouling was stable over three cycles of filtration without using a cleansing agent. The results suggested that PC waste could be used as a low-cost raw material for composite ultrafiltration membranes. [ABSTRACT FROM AUTHOR]

Amino-functionalized six-membered cyclic carbonate tert-butyl(2-oxo-1,3-dioxan-5-yl) carbamate (TBC) was synthesized with tert-Butyloxycarbonyl (Boc) as protected group. Due to its thermal properties, ring-opening polymerization (ROP) carried out in a relatively low temperature, and Sn (Oct)2 as catalyst. A series of copolymers were prepared with L-lactide (LA), ε-Caprolactone (CL) as co-monomers, searching for proper components and ratios. The protecting Boc-group was easy to remove by using trifluoroacetic acid (TFA). The structures of TBC and copolymers were confirmed by 1H NMR and 13C NMR analysis. Copolymers were characterized by DSC, GPC and water contact angle analysis. The introduction of pendant amino groups resulted in a significant enhancement of hydrophilicity of the copolymers. [ABSTRACT FROM AUTHOR]

The recent work evaluates the effect of ethylene methacrylate (EMA) as an impact modifier and the hybrid filler constitutes graphite flakes (GF), multiwalled carbon nanotubes (MWCNT), and steel fibers (SF) for the development of polycarbonate (PC) based conducting composite with high thermal conductivity and EMI shielding. The samples were initially optimized based on their mechanical properties, which were further characterized by thermal conductivity (TC) and electromagnetic interference shielding effectiveness (EMI SE). The thermal conductivity of the polycarbonate (PC) nanocomposites was found to increase by ~ 451% and ~ 602% at a significantly higher filler loading of 20 wt% and 30 wt% respectively without any processing difficulties. Further, the EMI SE values of the same have been enhanced in the range of -40.2 dB and -46.4 dB respectively, which falls within the range of commercially acceptable limits. Nonetheless, the results were indicative of the creation of a conductive network through the matrix, the electron microscopic and diffractometric studies confirmed the optimum dispersion of the hybrid filler system within the PC matrix. [ABSTRACT FROM AUTHOR]

The effects of multi-walled carbon nanotubes (MWCNTs) with different functional groups on the properties of the polycarbonate (PC)/poly (lactic acid) (PLA) was investigated. Non-functionalized (MWCNT), hydroxyl-functionalized (MWCNT-OH), carboxyl-functionalized (MWCNT-COOH), and polycarbonate-grafted multi-walled carbon nanotube (PC-g-MWCNT) were selected as nano-additives for PC/PLA. PC-g-MWCNT were prepared by reacting between the hydroxyl groups on MWCNT-OH and the carbonyl groups in PC by the reactive extrusion. Fourier transformed infrared spectroscopy (FTIR) analysis was performed to support the functionalization process and determined the chemical structure of the modified nanotube. MWCNTs were compounded with PC/PLA in a twin-screw micro compounder and moulded with the laboratory-scale injection moulding machine. Nano-additives was added to the polymer matrix at 3–5 wt.% loading levels. Characterization of the prepared samples was realized by the thermal, mechanical, electrical conductivity, and morphological analysis. As a result of FTIR analysis, nanotubes were seen to bind successfully to the PC. The best effect at onset decomposition temperatures was achieved by increasing about 39.8 °C with the addition of 5 wt.% MWCNT-OH to the PC/PLA. The highest elongation at break, tensile strength, and modulus was obtained for nanocomposites containing MWCNT-COOH. The selective localization of PC-g-MWCNT in the matrix provided the highest electrical conductivity in 5 wt.% PC-g-MWCNT added nanocomposite. [ABSTRACT FROM AUTHOR]

We investigated the distribution of the constituent polymers of an injection-molded product comprising a miscible blend of polycarbonate (PC) and low-molecular-weight poly(methyl methacrylate) (PMMA). We found that PMMA became localized at the surface without affecting the transparency of the product. As a result, the surface hardness was effectively enhanced by a small amount of PMMA. This technique can be used to produce an ideal plastic glass that has high transparency, mechanical toughness, and high surface hardness. [ABSTRACT FROM AUTHOR]

The mechanical behavior of polycarbonate (PC) polymer was investigated under the effect of various temperatures and strain rates. Characterization of polymer was carried out through uniaxial compression tests and split Hopkinson pressure bar (SHPB) dynamic tests for low and high strain rates respectively. The experiments were performed for strain rates varying from 10 to 10 and temperature range of 213 to 393 K. By conducting these experiments, the true stress-strain (SS) curves were obtained at different temperatures and strain rates. The results from experiments reveal that the stress-strain behavior of polycarbonates is different at lower and higher strain rates. At higher strain rate, the polymer yields at higher yield stress compared to that at low strain rate. At lower strain rate, the yield stress of the polymer increases with the increase in strain rate while it decreases significantly with the increase of temperature. Likewise, initial elastic modulus, yield and flow stress increase with the increase in strain rate while decreases with the increase in temperature. The yield stress increases significantly for low temperature and higher strain rates. On the basis of experimental findings, a phenomenological constitutive model was employed to capture the mechanical behavior of polymer under temperature and loading rate variations. The model predicted the yield stress of polymer at varying strain rate and temperature also it successfully predicted the compressive behavior of polymer under entire range of deformation. [ABSTRACT FROM AUTHOR]

Polymer foams with nanoscale cell structure were prepared from polycarbonate (PC)/poly (lactic acid) (PLA) blends. The immiscible blends with PLA as the dispersed phase were foamed through using batch foaming process and CO 2 as the physical foaming agent. Nanoscale cells emerged in both PLA domain and PC matrix of blend with 25 wt.% PLA content under an appropriate foaming condition. In the PLA domain, the formation of nanoscale pores was related to the confined foaming, blend and the crystallinity of PLA component. A transition from closed nanoscale cells to open nanoscale cells emerging in the PLA domain was in connection with the foaming condition. In the PC matrix, the cell property of the nanoscale cells was affected by the PLA phase. Moreover, the average cell sizes of nanocellular foams of both phases could be controlled within 40–130 nm by manipulating the size of PLA domain and saturation pressure. [ABSTRACT FROM AUTHOR]

This work demonstrates the physical properties for polymer nanocomposites of polycarbonate (PC) and functionalized-SWCNTs at different weight ratios. The results demonstrate that the thermal, rheological, electrical, and optical properties are significantly improved. The improvement over PC properties suggest that the functionalization of SWCNTs using UVO will improve their dispersion in the PC matrix and enhance their interaction with polymer matrix. The storage modulus value at RT is improved by 44 % as the weight fraction of SWCNTs increases up to 1 wt%. Electrical results show that the percolation threshold is around 0.4 % SWCNTs and incorporation of 1 % SWCNTs into PC will decrease PC resistivity up to six order of magnitudes. Incorporation of 1 % SWCNTs into PC will also enhance the UV/visible absorption and will decrease the optical energy gap of neat PC. [ABSTRACT FROM AUTHOR]

The degradation process of commercial grade Lexan® was investigated by thermogravimetric technique under isothermal experimental conditions at four different operating temperatures: 375 °C, 387.5 °C, 400 °C and 425 °C. The kinetic triplet ( E a, A, f( α)) was determined using conventional and Weibull kinetic analysis. The applied kinetic procedure shows that the investigated degradation process can be described by two-parameter autocatalytic Šesták–Berggren (SB) reaction model. It was established that the degradation process of Lexan® can be described by the following kinetic triplet: E a = 158.3 kJ mol−1, A = 8.80 × 109 min−1 and f( α) = α0.33 (1 − α)1.62. It was established that the operating temperature has an influence on the values of SB reaction orders ( m and n) (0.27 < m < 0.36 and 1.52 < n < 1.75). It was concluded that the apparent activation energy value of 158.3 kJ mol−1, represent the composite value from a complex degradation reaction and can not compare with the dissociation energy of the weak bonds in bisphenol-A polycarbonate. Also, it was concluded that the Weibull shape parameter ( β) shows that the considered process occurs under the same reaction mechanism, independently on operating temperature ( T), i.e. the change of rate-limiting step does not occur ( β < 1). In addition, it was established that the operating temperature has an influence on the basic characteristics of theoretically calculated density distribution functions ( ddf) of apparent activation energies for considered degradation process. On the other hand, it was shown that the experimentally evaluated density distribution function of apparent activation energies represents the intermediate case between the calculated density distribution functions at 375 °C and 425 °C. [ABSTRACT FROM AUTHOR]

Poly(trimethylene terephthalate) (PTT)/polycarbonate (PC) blends with different compositions were prepared by melt blending. The miscibility and phase behavior of melt-quenched and cold-crystallized blends were studied using differential scanning calorimetry (DSC) and dielectric relaxation spectroscopy. The blends of all compositions display only one glass transition ( T g ) in both states. The melting temperature and the crystallinity of PTT in the blend decrease with increasing PC content. The dielectric results for the melt-quenched blends, for PC content up to 60 wt.%, exhibited two merged relaxation peaks during the heating scan; the lower temperature relaxation peak represent the normal glass-transition (α) relaxation of the mixed amorphous phase and the higher temperature relaxation due to the new-constrained mixed amorphous phase after crystallization. Cold-crystallized blends displayed only one glass transition α-relaxation whose temperatures varied with composition in manner similar to that observed by DSC. The dielectric α-relaxation of cold crystallized blends has been analyzed. Parameters relating to relaxation broadening, dielectric relaxation strength, and activation energy were quantified and were found to be composition dependent. The PTT/PC blends could be considered as two-phase system, a crystalline PTT phase and a mixed amorphous phase consisting of a miscible mixture of the two polymers. However, the crystallinity was only detected for blends containing greater than 40 wt.% PTT. [ABSTRACT FROM AUTHOR]

The cationic reaction of an epoxy/BF3-MEA system occurs between the oxirane group and the oxonium group. The addition of polycarbonate to the system does not cause a transesterification reaction between the carbonate group and the oxonium group, thus the molecular weight of the PC is unchanged during the reaction. PC crystallization is observed in the cured system because the epoxy monomer accelerates the PC crystallization. The epoxy/BF3-MEA and epoxy/PC/BF3-MEA systems all follow the first order reaction. The PC modified systems show lower activation energy, a lower pre-exponential factor and a higher reaction rate constant. [ABSTRACT FROM AUTHOR]

Novel P-containing copolycarbonate was prepared via melt polycondensation of diphenyl carbonate (DPC), bisphenol-A (BPA) and 2-(6-oxid-6H-dibenz〈;c,e〉〈1,2〉oxa-phosphorin-6-yl)-1,4-benzenediol (ODOPB). The copolycarbonates were characterized by infra-red spectra, reduced viscosity, and differential scanning calorimetry. The copolycarbonates with reduced viscosities of 0.21∼0.25 dL/g were obtained in quantitative yields. These phosphorus containing copolycarbonates have excellent thermal and flame retardant properties. Owing to the incorporation of the rigid structure of ODOPB and the pendant P group, the resulting phosphorus containing copolycarbonates exhibited better flame retardancy, higher char yield, higher degradation temperature and thermal stability than homopolymers of polycarbonate (PC). High LOI value and UL 94-VO rating could be achieved with a phosphorus content of as low as 0.75% for PC, and no fumes or toxic gas emissions were observed. [ABSTRACT FROM AUTHOR]

PC-DER331 blends are transparent and homogeneous due to the transesterification taking place during hot melting process. This transesterification reaction does not occur or occurs insignificantly during the preparation of PC-DER332 blends. PC is separated from the PC-DER332 melt mixture by slow cooling to room temperature but the mixture remains a single phase by quenching with an ice bath. Two systems of PC-epoxy blends, PC-DER331 blends and PC-DER332 blends are cured by the m-phenylene diamine (MPDA) in a stoichiometric ratio. Curing kinetics have been carried out by differential scanning calorimeter (DSC). The presence of PC accelerates the curing reaction. Infrared spectroscopy (IR) indicates the occurrence of transesterification in the PC-DER331/MPDA blends during curing. The flexural modulus increases with the increase of the PC content while the notched Izod impact strength decreases with the increase of the PC content for all the blending systems. The fracture surfaces of the PC-DER331/MPDA blends are smooth, an indication of a homogeneous morphology. The fracture surfaces of the PC-DER332/MPDA blends are rough, an indication of a heterogeneous morphology. [ABSTRACT FROM AUTHOR]

The variations of the flow induced phase morphology of fluoroelastomer/polycarbonate (FL/PC) extruded blends and their mechanical properties were investigated in this paper. The phase morphology and mechanical property of extruded blends under the capillary die were examined by scanning electron microscope (SEM) and tensile machine, respectively. From SEM observation, the dispersed phases in the longitudinal direction for these extruded blends were categorized as sphere, ellipsoid, rod, and fiber. Furthermore, the processing window for the deformation of phase morphology in the longitudinal direction for FL/PC 10/90 w/w and 25/75 w/w extruded blends at 235 and 260 °C was studied. As shear stress was smaller than 7.0 × 104 Pa, the spherical phase almost did not deform. The transformation from the sphere to the fiber form occurred in the range of shear stress 7.0 × 104 Pa and 15.8 × 104 Pa. In particular, as shear stress was larger than 15.8 × 104 Pa, the fiber broke up into a series of small droplets. Finally, it was concluded that the morphology with the mixture of fiber-like and spherical structures in the longitudinal direction could enhance the FL/PC blends with longer break elongation and higher Young’s modulus. [ABSTRACT FROM AUTHOR]

The transport of CO2 through variety of polymer membrane has been reported since last few years. CO2 shows plasticizing effect with glassy polymers facilitating molecular motion and increasing free volume which promotes the permeability. In this work, the transport behaviour of CO2 across the metal coated membrane has been studied and compared with that of standard polycarbonate membrane as a function of pressure. Deposition of nanolayer affects the transport properties due to the modification in sorption-diffusion process. As CO2 is a plasticizing agent and at definite pressure it gives plasticizing effect depending on the properties of material. A Platinum-Palladium (Pt-Pd) alloy thin film of around 8–10 nm was coated on thick polycarbonate (PC) substrate using sputtering technique to make layered polymer nanocomposite membrane. The permeability decreases with feed pressure for PC/Pt-Pd. As operating pressure is increased, the diffusion coefficient increases with small change and the solubility decreases. The tests were carried out at different upstream pressures i.e. in the range of 30 psi to 230 psi (2 atm to 16 atm) for PC/Pt-Pd at 35 °C temperature. Further, the selectivity of CO2 over H2, O2 and N2 at various upstream pressures has been reported. [ABSTRACT FROM AUTHOR]