Polycarbonate Matrix Research Articles

A P/Si-containing flame retardant towards simultaneous improvement of the toughness, transparency and fire safety of polycarbonate

Polycarbonate (PC) is a commonly used engineering plastic, but its poor flame retardancy limits its use. In this study, a DOPO-based flame-retardant (DOPO-TMTA) containing P and Si elements was synthesized via a simple method involving 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and 2, 4, 6-trivinyl-2, 4, 6-trimethylcyclotrisiloxane (TMTA). The PC/mDOPO-TMTA (m = 4, 6, 8) composites were prepared by melt blending PC with different loadings of DOPO-TMTA. The prepared PC/DOPO-TMTA composites had excellent flame retardancy while maintaining good transparency. The limiting oxygen index (LOI) of PC/8DOPO-TMTA reached 32.5 % and achieved a UL-94 V-0 rating. Moreover, cone calorimetry tests revealed that, compared with those of pure PC, the peak heat release rate (PHRR) and total heat release (THR) of PC/8DOPO-TMTA decreased by 39.0 % and 38.1 %, respectively. Compared with pure PC, PC/mDOPO-TMTA also maintained good mechanical properties, and the tensile and impact strengths were slightly improved. The synergistic flame retardancy of DOPO-TMTA on P/Si elements for the PC matrix was revealed by condensed phase and gas phase product analysis. This work provides a good reference for the preparation of PC composites with high transparency and excellent comprehensive properties.

Compatibilizing and foaming of PC/PMMA composites with nano‐cellular structures in the presence of transesterification catalyst

AbstractCompatibility of polycarbonate (PC) and polymethyl methacrylate (PMMA) alloys was improved by using a transesterification catalyst (SnCl2·2H2O). Modified PC/PMMA alloys exhibit single Tg, and their initial island phase existing in the SEM were transformed into uniform surface. Besides, the transmittance of the modified alloys was increased from original 40% to 85%. Moreover, PC/PMMA alloys and PC foams with micro‐cellular and nano‐cellular structures were prepared by solid‐state CO2 foaming in the presence of transesterification catalyst. Distinctively, there are obvious nano‐cellular structures existing in the PC samples, but no related nanostructures were found in PMMA samples, after treated by same amount of catalyst and foaming process for pure PC and PMMA matrix. Furthermore, the effects of foaming temperature and segment structure on their foaming behavior were also studied. Additionally, a uniaxial stress experiment was conducted at a specific temperature to simulate the biaxial stress during the foaming process for discovering the mechanism of nanopore formation. Therefore, the concept of nano‐cellular structures will point out a direction for the development of high‐performance, heat insulation PC materials of the next generation.Highlights Transesterification catalysts enhanced compatibility between PC and PMMA. Nanopore structures were successfully constructed in PC foams. Segment stretching was the main reason for the formation of nanopores.

In Situ Formation of Compound Eye-like SAN-OSB Composite Microspheres by Melt-Blending Method: Enhancing Multiple-Scattering Effect.

The preparation of novel structures of light-diffusing particles is currently a research focus in the field of light-diffusing materials. This study, conducted by the common melt-blending process, controlled thermodynamic and kinetic factors to distribute smaller-sized organic silica bead (OSB) particles at the interface between a polycarbonate (PC) matrix and spherical island-phase styrene-acrylonitrile copolymer (SAN) for the in situ formation of compound eye-like microspheres with SAN as "large eyes" and OSBs as "small eyes". Through the multiple-scattering effects of these compound eye-like microspheres, these light-diffusing materials significantly improved the haze, scattering range, and light-shielding capabilities while maintaining high transmittance. Specifically, the PC/SAN-OSB light-scattering materials achieved a haze of 100% with an OSB content of only 0.17%, maintaining a transmittance of 88%. Compared with the PC/OSB system with the same level of haze, the addition of OSB was reduced by 88%. Therefore, this study achieved exceptionally effective light-diffusing materials through a simple, environmentally friendly, and low-cost preparation method, suitable for the scalable production of light-diffusing materials in new display and lighting fields.

Sustainable 3D printing with alkali-treated hemp fiber-reinforced polycarbonate composites

The study investigated the properties of alkali-treated hemp fiber-reinforced polycarbonate (PC) composites that can be formed by 3D printers for architectural applications. To determine the optimum alkali treatment to be applied to the fibers, the properties of the samples treated with 5% and 7% sodium hydroxide (NaOH) at both ambient temperature (AT) and 120 °C (HT) were determined by Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). It was determined that the alkali treatment that gave the optimum result was 5% HT. Composite specimens with fiber/matrix ratios of 10/90, 20/80, and 30/70 were prepared in filament form to be printed in a 3D printer as alkali-treated and untreated. These composites were characterized by conducting tensile strength, FTIR, differential scanning calorimetry (DSC), TGA, and scanning electron microscopy (SEM) analyses. Tensile strength results revealed the highest mechanical performance for 5% NaOH alkali-treated and 10 wt.% hemp fiber-reinforced PC composites. DSC results showed that slight changes occurred in the glass transition temperature values. Furthermore, SEM analysis showed that 5% NaOH-treated hemp fibers have better interfacial bonding with the PC matrix than untreated fibers. As a result, more natural and sustainable materials have been obtained for architectural applications without significantly decreasing in PC properties.

Organic-Inorganic Hybrid Materials: Tailoring Carbon Dioxide-Based Polycarbonate with POSS-SH Crosslinking.

A novel functional polycarbonate (PAGC), characterized by the presence of double bonds within its side chain, was successfully synthesized through a ternary copolymerization of propylene oxide (PO), allyl glycidyl ether (AGE), and carbon dioxide (CO2). Polyhedral oligomeric silsesquioxanes octamercaptopropyl (POSS-SH) was employed as a crosslinking agent, contributing to the formation of organic-inorganic hybrid materials. This incorporation was facilitated through thiol-ene click reactions, enabling effective interactions between the POSS molecules and the double bonds in the side chains of the polycarbonate. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) confirmed a homogeneous distribution of silicon (Si) and sulfur (S) in the polycarbonate matrix. The thiol-ene click reaction between POSS-SH and the polycarbonate led to a micro-crosslinked structure. This enhancement significantly increased the tensile strength of the polycarbonate to 42 MPa, a notable improvement over traditional poly (propylene carbonate) (PPC). Moreover, the cross-linked structure exhibited enhanced solvent resistance, expanding the potential applications of these polycarbonates in various plastic materials.

Rubber-based phosphaphenanthrene grafted polymer and its application to fabricate flame retardant polycarbonate blend with satisfied comprehensive mechanical properties

Grafting flame retardant groups onto common polymer molecule can be a good strategy to constructing superior flame retardant macromolecules, which provides a promising direction to fabricate fire safety polymer materials with satisfied comprehensive mechanical properties. In this thesis, a rubber-based phosphaphenanthrene grafted polymeric molecule (P-SBS) was synthesized via the grafting reaction of 9, 10-dihydro-9-oxa-10-phenanthrene-10-oxide (DOPO) with thermoplastic styrene-butadiene-styrene copolymer (SBS), and then applied to melt blending with polycarbonate (PC) to form P-SBS/PC blend with sea-island structure. The incorporated P-SBS not only brought PC much higher comprehensive flame retardancy, including higher limited oxygen index, shorter self-extinguishing time, less heat release during burning process, higher-quality char layer structure, and fewer amount of flammable volatile emission; but also endowed it with more satisfied comprehensive mechanical properties, including larger elongation at break, better anti-impact, higher flexural strength, and maintained tensile strength. By analysing burning residue, tracking thermal decomposition volatile emission, and inferring the pyrolysis route of P-SBS, the gas- and condensed-phase flame retardant mechanisms of P-SBS in suppressing the flammability of PC matrix were disclosed. The morphology analysis on the matrix fracture section and the embeded P-SBS particles before and after mechanical fracture, revealed the behavioral mechanism of P-SBS particles in improving the ductility, toughness, and stiffness of PC matrix. This study provides a beneficial reference to superior flame retardant molecule constructing and advanced flame retardant polymer material manufacturing.

Science in 2025-2027 and the SPQEO journal

Relevance of recent research is important for scientists and journals reporting research results. There are many sources of prognoses and one of them is the Report of European Commission "Looking into the R&I future priorities 2025-2027". It predicts the importance of the following areas for users: healthcare, energy, climate, sustainability and digitalization. The Ukrainian journal Semiconductor Physics, Quantum Electronics and Optoelectronics (SPQEO) actually focuses on these areas and contributes to the development of related knowledge. Monitoring of last SPQEO issues shows some interesting results: (i) the effect of local field amplification, which causes emergence of ponder motive forces acting on viruses until destruction of viral envelopes; (ii) the methods of malignant tumors treatment taking into account their genesis mechanisms and focusing on correction of definite pathogenesis components, while being nontoxic for other organs and tissues; and (iii) manipulation of the spectral characteristics of a “polycarbonate matrix – gold nanostructures – HTTH dye” system due to influence of gold nanostructures. SPQEO paid attention to the improvement of solar cells (SCs) by considering physical effects such as the effect of space charge region (SCR) recombination on the key characteristics of high-efficiency silicon solar cells, such as photovoltaic conversion efficiency and open-circuit voltage, is not only dependent on the charge-carrier lifetime in the SCR, but also on the ratio of hole-to-electron-capture cross section, σp/σn. Non- traditional SCs were also considered: SCs with perovskite thin films, SCs comprising CdS/CIGS heterojunctions, and vitamin B12-patterned silicon hybrids based SCs. Moreover, SPQEO also covers research results in the fields of quantum devices, diamond- like and oxide films, and light-emitting diodes.

A novel macromolecular phosphorus-nitrogen containing flame retardant for polycarbonate

In this paper, an innovative macromolecular phosphorus-nitrogen containing flame retardant (PDPSB) was successfully designed and synthesized to investigate its impact on the flame retardancy, burning behavior, thermal stability, mechanical properties of polycarbonate (PC) composites. Furthermore, an in-depth exploration of the potential flame-retardant mechanism was conducted. The combustion results indicated that PC-3 with 3 wt% PDPSB reached V-0 rating in UL-94 test and showed a high limiting oxygen index (LOI) of 33.0 %. Compared to pure PC, the values for peak of heat release rate (PHRR), total heat release (THR) and total smoke production (TSP) of PC-3 were decreased by 37.9 %, 11.1 % and 4.9 %, respectively. It was noteworthy that the amount of char residue for PC-3 was raised from 7.4 % for pure PC to 15.8 % with increasing 113.5 %. The thermogravimetric analysis (TGA) results under N2 atmosphere revealed that PDPSB possessed preferable thermal stability with initial decomposition temperature (Tinitial) of 342.6 °C and higher char residue yield of 48.4 %. With increasing the amount of PDPSB, the maximum mass loss rate (Rpeak) was reduced and the char residue yield was increased for PC/PDPSB composites. In addition, the mechanical properties of PC/PDPSB composites were well maintained due to the good compatibility and dispersion between PDPSB and PC matrix. The tensile, flexural and izod impact strength of PC-3 were weakened by 4.3 %, 1.7 % and 16.8 % in comparison of pure PC, respectively. Based on the investigation into the flame-retardant mechanism of PDPSB, the excellent flame retardance of PC/PDPSB composites has been validated. In gaseous, the release of pyrolysis gases was suppressed and active radicals were captured by generated phosphorus free radicals. In condensed phase, the stable char residue with phosphorus and nitrogen elements acted as a barrier to hinder heat, flame and oxygen. This high-efficient single-component multifunctional additive presented a novel approach to the development of fire-resistant polymers with enhanced performance characteristics.

(Digital Presentation) Unraveling of the Morphology and Chemistry Dynamics in the FEC-Generated Silicon Anode SEI across Delithiated and Lithiated States

The silicon solid electrolyte interphase (SEI) faces cyclical cracking and reconstruction due to the ~350% volume expansion of Si which leads to shortened cell life during electrochemical cycling. Understanding the SEI morphology/chemistry and more importantly its dynamic evolution from delithiated and lithiated states is paramount to engineering a stable Si anode. Fluoroethylene carbonate (FEC) is a preferred additive with widely demonstrated enhancement of the Si cycling. Thus, insights into the effects of FEC on the dynamics of the resulting SEI may provide hints toward engineering the Si interface. Herein, ATR-FTIR, AFM, tip IR, and XPS probing all show pronounced relative invariance of the FEC-generated SEI compared to the FEC-free SEI between adjacent lithiated and delithiated states beyond the formation cycles. The SEI of Si thin film model surfaces in the baseline 1 M LiPF6 in EC:EMC (1:1) undergoes major morphological and chemical speciation swings between half-cycles while comparatively the SEI upon addition of FEC displays far less dynamic evolution. This morphology and chemistry stability of the FEC-SEI supports the enhanced cycling stability of silicon anodes in FEC-containing electrolytes. The experimental evidence gathered suggests that the FEC-SEI invariance is enabled by an elastomeric polycarbonate matrix that preserves the SEI integrity against the expansion of silicon upon lithiation. In turn, less electrolyte-consuming reconstruction occurs which manifests as and high LiF content from one half-cycle to the next. This work provides critical insights to enhance the silicon anode stability via targeted SEI engineering, namely that LiF protected by an elastomeric protective matrix may be key to buffering the unavoidable mechanical disruption. Figure 1

Influence of gold nanostructures on excited state intramolecular proton transfer in multidomain HTTH dye

Organic multidomain dyes exhibiting excited state intramolecular proton transfer (ESIPT) are known due to large Stokes shifts and dependence of their luminescence spectral characteristics on the properties of the environment. In this work, influence of gold nanostructures on the spectral characteristics of a “polycarbonate matrix – gold nanostructures – HTTH” system was studied using thiazole dye HTTH as an example. A hypothesis about the possibility of plasmon resonance energy transfer (PRET) between the HTTH molecules in different states, namely the ground state (enol form) and the state after proton transfer (keto form), mediated by gold nanostructures was experimentally tested. Presence of gold nanostructures in the vicinity of HTTH molecules was found to lead to the changes in the ratio of the luminescence peak intensities for the enol and keto form of these molecules. This phenomenon opens up the possibility of additional regulation of the spectral characteristics and may evidence the PRET effect in the systems containing ESIPT-exhibiting dyes and plasmonic nanostructures. The obtained results improve our understanding of the physical processes in the systems similar to the studied one and imply new practical applications of them such as fabrication of organic light-emitting diodes, sensors, super-resolution microscopy tools and ultraviolet-to-visible radiation convertors.

A comparative study of polycarbonate nanocomposites respectively containing graphene nanoplatelets, carbon nanotubes and carbon nanofibers

In industrial settings, thermoplastics are frequently employed as the base materials for composites and often enhanced with micron-sized additives such as glass fibers for improved performance. This study employed twin-screw extrusion as the processing method to compound a common thermoplastic – polycarbonate (PC) with one dimensional (1D) multi-walled carbon nanotubes (MWCNTs), carbon nanofibers (CNFs) and two dimensional (2D) graphene nanoplatelets (GNPs). In the PC matrix, GNPs were found to relatively uniformly dispersed, MWCNTs were seen to have two states of dispersion, and CNFs were much shortened with many defects caused by the extrusion. At 10.0 wt%, MWCNTs reduced the electrical resistivity of PC from 4.2 × 1015 to 4.6 × 107 Ω·cm, and GNPs improved the thermal conductivity from 0.13 to 0.38 W·m−1·K−1. GNPs, MWCNTs and CNFs at 1.0 wt% all improved the mechanical properties of PC, i.e. increments of 13.8%, 5.7% and 13.8% for Young's modulus, 6.2%, 11.7% and 21.2% for tensile strength, and 9.6%, 10.2% and 5.7% for impact strength. At 10.0 wt%, the PC/GNP nanocomposite displayed the least reduction of tensile strength of PC whilst the PC/CNF nanocomposite slightly increased the un-notched Charpy impact strength from 161 to 186 kJ/m2. The structure-property relationship of these nanocompsoites was analysed, with the relavent mechanisms proposed. Overall, twin-screw extrusion proved effective for dispersing various carbon nanomaterials in PC. This work provides a guide for industry to design and manufacture thermoplastic/carbon nanomaterial composites using the extrusion method.

Polycarbonate composites for material extrusion-based additive manufacturing of thermally conductive objects

Enhanced thermally conductive polymer composites can be used in many engineering applications where either the physicochemical properties of plastics or the processing properties of plastics are required. Rapid prototyping is currently being addressed for a number of applications that require good heat transfer properties. Such applications include various types of heat exchangers containing coolant/heating fluid as well as passive heat sinks for standard heat removal from various types of heat-generating products. The present work is focused on the research of thermally conductive composites for printing such structures using additive manufacturing (AM), namely material extrusion. In this study, a number of parameters of the composites were investigated that affect the final properties of the printed structures; these include the TC (Thermal Conductivity), mechanical properties, and printability of the composites, depending on the composition, but also the printing direction. The composites studied were made up of a matrix of PC (Polycarbonate) and a mixture of different thermally conductive fillers, specifically, h-BN (Hexagonal Boron Nitride), EG (Expanded Graphite), PCFs (Pitch-based Carbon Fibers) and Al (Aluminum Particles). Different types of thermally conductive composites were studied, from binary to ternary combinations of fillers. One of the best-performing composites was achieved for the combination of all four types of filler, where thermal conductivity along the printing direction was achieved for the PC matrix with 30 wt% of the mixture of all fillers. Up to 1.56 W m−1 K−1 was achieved, which is 5-fold higher than for neat PC. Although these composites have approximately half the tensile strength only, the hardness is similar to that of the neat PC. The behavior of fillers was observed by SEM analysis. Al, EG, and PCFs behave predictably. Unusual behavior was observed in the case of PC only with h-BN, where the filler migration from the matrix to the voids between the non-fused printing paths occurred, likely caused by a larger amount of dispersion component of the overall surface energy of h-BN. Such phenomena could be used in the optimized form in the future so that segregated thermally conductive structures could be created using material extrusion-based AM and allow even higher thermal conductivity of final structures.

Hexaphenoxy cyclotriphosphazene/boron nitride high-efficiency charring system enhancing the flame retardancy and thermal conductivity of polycarbonate

Polycarbonate (PC), as an engineering plastic, has excellent mechanical properties and electrical insulation properties. Nevertheless, with the rapid spread of 5 G applications, there is an increasing demand for functional PC materials with both thermal conductivity and flame retardant properties. In this study, the flame retardant thermal conductivity composite system of boron nitride (BN) and hexaphenoxy cyclotriphosphazene (HPCP) was constructed to study the simultaneous improvement of the flame retardant and thermal conductivity of PC. The results reveal that the inclusion of HPCP and BN in PC can significantly enhance its flame retardancy. This enhancement is evidenced by prolonged ignition time, reduced heat release rate and decreased total smoke production. In particular, 20BN/3HPCP/PC composite shows the best flame retardant effect. Through the investigation of flame retardant mechanisms, it has been found that the network structure formed by the BN sheets with phosphorus-containing products of HPCP decomposition can effectively filter and adsorb pyrolysis debris and increase the residence time of burning fragments in the pyrolysis zone promoting the pyrolysis products further fully burned to reduce the smoke caused by incomplete combustion. The phosphoric acid substances after the decomposing of HPCP can promote PC matrix to dehydration and carbonization to form the phosphorus-containing residues, which adheres on the BN network structure to form hardness char layers in the condensed phase to play an excellent role in blocking heat and combustible flue gas, which has a positive effect on reducing heat release rate and improving flame suppression. In terms of improving thermal conductivity, the infrared thermal imaging experiment further confirmed that BN sheets can increase the thermal conductivity of PC composites by more than 4 times, and the layer and layer stacks structure of BN sheets can endow an efficient thermal conductivity path for PC matrix to improve the thermal conductivity. Therefore, this study is meaningful practical exploration for developing the PC composites with excellent thermal conductivity and flame retardancy.

Boron-doped copper phenylphosphate as temperature-response nanosheets to fabricate high fire-safety polycarbonate nanocomposites

The application of polymer materials has provided the convenience and also bring fire risk and hazard due to intrinsic flammable property of polymers. Here we demonstrate a novel strategy using boron-doped copper phenylphosphate (BCuPP) nanosheets with temperature-response characteristics as only flame retardant for creating high fire-safety polycarbonate (PC) nanocomposites with excellent comprehensive performances. PC/BCuPP nanocomposites presents a good mechanical performance at room temperature due to the strong interfacial interaction between PC matrix and BCuPP nanosheets. Furthermore, BCuPP exhibits unique temperature-response behavior driven by fire, where fully molten boron oxide flows freely, followed by in-situ formed BPO4 to repair the defects to form a complete and continuous protective layer. So the temperature-response behavior endows PC/BCuPP nanocomposites excellent fire-safety performance with dramatical decrease in both heat release rate and total smoke production. This study offers a novel route only incorporating nanoparticles as flame retardant to create high fire-safety polymer nanocomposites.

A nitrogen‐rich DOPO‐based phosphoramide for improving the fire resistance of polycarbonate with comparable mechanical property

AbstractA nitrogen‐rich DOPO‐based phosphoramide (DPAPZ) was synthesized using aminopyrazine and 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO) as raw materials, and blended with polycarbonate (PC) through melting method. The chemical structure of DPAPZ was validated by FTIR, 1H NMR and 31P NMR. The presence of DPAPZ endowed PC/DPAPZ composites with better fire safety and smoke suppression. With the incorporation of 6 wt% DPAPZ, PC/DPAPZ‐6 composite reached UL‐94 V‐0 rating and 30.2% of limiting oxygen index value. Simultaneously, the peak of heat release rate and total heat release of PC/DPAPZ‐6 were reduced by 44.8% and 47.0% as compared with the pure PC, respectively. The DPAPZ displayed bi‐phase flame retardant roles. In the gas phase, the decomposition of DPAPZ released phosphorus‐containing free radicals acting as the quencher of reactive H·/OH· and nonflammable NH3 diluting O2/combustible volatiles. In the condensed phase, the phosphorus‐containing components were dehydrated into metaphosphoric acid or polymetaphosphate covering the surface to protect the PC matrix from further combustion, and to promote the formation of a dense carbon layer to interrupt the transmission of O2 and volatiles between the combustion zone and the inner. The tensile strength of the composites displayed almost no change but the elongation at break decreased slightly with the addition of DPAPZ.

Trace-level sensing of food toxins by flexible and cost-effective SERS sensors fabricated by pulsed-laser-deposition of gold nanoparticles on polycarbonate matrix

In viewpoint of rapid onsite screening of food contaminants, flexible surface enhanced Raman spectroscopy (SERS) sensors are developed by pulsed laser deposition process (PLD) with plasmonic gold nanoparticles (AuNPs) on the polycarbonate (PC) polymer matrix in the current study. PC/AuNPs with varying laser ablation pulses (200 NLP to 5000 NLP) tailored the morphological, structural and optical properties with their size and shape confinements. SERS properties of the prepared flexible PC/AuNPs sensors were optimized with Raman probe dye Rhodamine 6 G (R6G). Exorbitant SERS efficiency with highest enhancement factor of 1.1 × 108 was noted with sensor prepared at 3000 NLP (PA 3000 NLP). Sensor surface uniformity exhibited greater signal reproducibility with low values of % RSD (7.8). The fabricated flexible SERS sensor (PA 3000 NLP) achieved sensing of the food toxins effectively even in their trace levels of 10 − 10 M for methyl orange (MO) and 10 ppm for Butylated hydroxy anisole (BHA). Mechanism of SERS sensing dominated the electromagnetic enhancement was correlated well with their properties. Since SERS sensing need not require any intricate analyte pre-treatment, the fabricated PA 3000 NLP flexible SERS sensor can find the food toxins in rapid time (< 2 min), projecting a portable platform to conserve food safety.

The Influence of Fiber Treatment and Matrix Type on the Impregnation Quality of Carbon Fiber Reinforced Thermoplastics

One of the main issues with Carbon Fiber Reinforced Thermoplastics (CFRTP) is the poor impregnation quality of the matrix on carbon fiber due to the high viscosity of the thermoplastic. Impregnation quality can significantly affect the mechanical properties of the composite. This study aims to compare the impregnation abilities of various types of thermoplastic matrices on carbon fiber. The matrices used in this study are HDPE, PC, and PET. Three variations of carbon fiber treatment were employed: the first variation involved immersion in liquid nitrogen at -196°C, the second variation included heating in an electric furnace at 600°C followed by rapid cooling in liquid nitrogen, and the third variation utilized treatment with a silane coupling agent. The research findings demonstrate that composites comprising a Polycarbonate matrix and carbon fiber reinforcement, treated with a silane coupling agent, exhibit superior impregnation quality, as evidenced by an Interfacial Shear Strength (IFSS) value of 9.34 MPa.. The lowest impregnation quality was observed in HDPE reinforced with carbon fiber that had been heated and rapidly cooled, with an IFSS of 5.52 MPa.

Micro-crosslinking of phosphaphenanthrene/siloxane molecule initiate aggregation flame retardant and toughening enhancement effects on its polycarbonate composite

The precise construction of molecular functional systems is an important way to develop high-performance flame retardant polymer composites with excellent comprehensive mechanical properties. A micro-crosslinked macromolecule (PMD) with group aggregation features has been synthesized from vinyl monomers (MD) bearing phosphaphenanthrene and cyclotetrasiloxane groups. The micro-crosslinking polymerization of MD results in superior structural stability and charring capability. PMD not only endows the polycarbonate (PC) composite with excellent comprehensive flame retardant performance, but also maintains the flexural and tensile properties of the PC matrix, as well as an enhanced anti-impact performance. More importantly, when compared with congeneric low molecular weight contrast, PMD exhibits much higher efficiency in suppressing the combustibility of the PC composite. A toughening effect on the matrix was only observed in the PMD/PCs upon increasing the additive content that did not appear in MVCD/PCs, which fractured more easily. 5 %PMD/PC passed the UL94 V-0 rating with a LOI value of 36.3%, and achieved 31.4% higher impact strength, 46.4% lower pk-HRR, 26.7% longer time to pk-HRR, 57.1% lower FGI, 57.7% higher FPI, and 25.6% lower peak of CO production rate when compared with those of the initial sample. The toughening and flame retardant mechanisms of PMD were also revealed upon analyzing the resultant micro-/macro- morphology and chemical components of the char residue, thermal decomposition volatiles, and pyrolytic fragments. These provide a beneficial molecular-structure construction reference for developing high-performance polymer composites with excellent comprehensive performance in both of flame retardancy and mechanical properties.

The Study of Crystallization Behavior, Microcellular Structure and Thermal Properties of Glass-Fiber/Polycarbonate Composites

Polycarbonate (PC) foam is a versatile material with excellent properties, but its low thermal stability limits its application in high-temperature environments. The aim of this study was to improve the thermal stability of PC foam by adding glass fibers (GF) and to investigate the effect of GF on PC crystallization behavior and PC foam cell morphology. This study was motivated by the need to improve the performance of PC foams in various industries, such as construction, automotive, and medical. To achieve this goal, PC/GF composites were prepared by extrusion, and PC/GF composite foams were produced using a batch foaming process with supercritical carbon dioxide (SC-CO2) as the blowing agent. The results showed that the addition of GF accelerated the SC-CO2-induced crystallization stability of PC and significantly increased the cell density to 4.6 cells/cm3. In addition, the thermal stability of PC/GF foam was improved, with a significant increase in the residual carbon rate at 700 °C and a lower weight loss rate than PC matrix. Overall, this study highlights the potential of GF as a PC foam reinforcement and its effect on thermal and structural properties, providing guidance for industrial production and applications.

Dielectric Response of Strontium Titanate (SrTiO3)/Polycarbonate Nanocomposite Electrodes for Energy Storage

In the present study we are reporting dielectric response of strontium titanate (SrTiO3 represented as ST used as filler in 1–5 mwt%)/polycarbonate (PC) nanocomposites of thickness 100 μm synthesized by solution cast method. Polycarbonate serving as passive matrix element and ceramic strontium titanate (SrTiO3) dispersed into polycarbonate to improve effective dielectric response. X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and Scanning electron microscopy (SEM) have been used to investigate structural, bonding and morphological properties of fabricated nanocomposites respectively. Particular attention has been given on the examination of dielectric response for composites using Impedance analyzer. Dielectric constant has been found to be increased with increasing concentration of SrTiO3 inside the polycarbonate matrix. The observed dielectric constant reaches upto 6.61 for ST5%PC95% composite at 1 KHz. These composites of high dielectric constant can be used as high performance electrode materials for electrical energy storage devices.