Copolymer Poly Ethylene Research Articles

Amphiphilic block‐copolymer exfoliated transition metal dichalcogenides as novel epoxy toughening agents

AbstractExcited by the effect of amphiphilic block copolymer Polyethylene glycol‐b‐Polypropylene Glycol‐b‐Polyethylene Glycol, a triblock copolymer (TBCP) in the virgin state as well as in the grafted form with graphene oxide and multiwalled carbon nanotube in epoxy toughening, the effect of the same block copolymer in the exfoliation of graphene analogous Transition Metal Dichalcogenides (TMDs) was studied. Even though epoxy resin has several advantages, its inherent brittleness and flammability limit its application in several areas. So, there is a need for the efficient toughening of epoxy resin to make it appropriate for high‐end applications. In the present work, epoxy resin was toughened with exfoliated TMDs, especially Molybdenum sulfide and Tungsten disulfide (MoS2 and WS2). TBCP was used in the exfoliation of TMDs where the effect of these exfoliated TMDs in enhancing the properties of epoxy was evaluated. TBCP exfoliated MoS2 and WS2 exhibit fracture toughness of 483% and 636%, respectively in epoxy composites without compromising the tensile properties, which enhances the efficacy of epoxy resins towards high‐end applications. The improvement in toughness is evident from the fractography of the crack surfaces. The role of TBCP exfoliated TMDs in tuning the mechanical, thermal, and thermomechanical properties is portrayed in the manuscript, thereby unveiling the potential of yet another unique class of materials in epoxy toughening.Highlights The efficiency of amphiphilic block copolymer in exfoliating TMDs is analyzed. The effect of TBCP‐exfoliated TMDs as a toughener for the epoxy matrix is portrayed. 483% and 636% improvement in the toughness compared to neat epoxy was obtained for TBCP exfoliated MoS2 and WS2 reinforced epoxy respectively. Improved tensile properties after incorporation of TBCP exfoliated TMDs in epoxy matrix. The plasticizing effect of TBCP compromises the thermal properties.

Crystallization Behavior of Block Copolymers of Isotactic Polypropylene and Linear Low-Density Polyethylene

Crystallization Behavior of Block Copolymers of Isotactic Polypropylene and Linear Low-Density Polyethylene

Crystallization Kinetics of Crystalline–Crystalline and Crystalline–Amorphous Block Copolymers of Linear Polyethylene and Isotactic Polypropylene

Crystallization Kinetics of Crystalline–Crystalline and Crystalline–Amorphous Block Copolymers of Linear Polyethylene and Isotactic Polypropylene

Analytical ultracentrifugation study of complex formation between like-charged glycinin and polyelectrolytes: Impact of ionic strength and chain length

In food systems, complexes formed between soybean protein and polyelectrolytes are extensively utilized. However, the mechanisms governing their interactions remain elusive, especially when they possess similar net charges. This study investigates the complexation between like-charged glycinin (11S) and diblock copolymers of polyethylene glycol-block-poly(sodium styrene sulfonate) (PEG-b-PSS) using analytical ultracentrifugation (AUC), a first-principle technique that examines macromolecular characteristics such as molecular weight, stoichiometry, and binding properties. The results reveal that 11S can interact with polyelectrolytes of the same net charges. At ionic strengths above 0.1 M, under a specific concentration of PEG-b-PSS with a PSS degree of polymerization of 33, reducing ionic strength augments the binding strength between PEG-b-PSS and 11S while enhancing the electrostatic repulsion between complexes. Consequently, association occurs as ionic strength decreases from 0.5 to 0.3 M due to the predominance of binding strength, and the association disappears at 0.1 M because electrostatic repulsion becomes predominant. Moreover, PEG-b-PSS with a higher degree of polymerization in the PSS blocks facilitates the formation of insoluble complexes of 11S via soluble intermediates. At an ionic strength of 0.025 M, PEG-b-PSS induces the dissociation of 11S into subunits and peptides. This study demonstrates that by controlling the ionic strength and the degree of polymerization of the polyelectrolyte, it is possible to regulate the binding strength between 11S and polyelectrolyte, as well as the structural changes during binding. Furthermore, this study contributes to understanding the complex formation mechanism between soybean protein and polyelectrolytes, and further expands the application of AUC in studying their binding.

Synthesis of Ordered Mesoporous Transition Metal Dichalcogenides by Direct Organic–Inorganic Co‐Assembly

AbstractEndowing transition metal dichalcogenides (TMDs) with mesoporous structure can greatly enhance their porosity, accessible specific surface area, and exposed active sites, leading to better performances in applications based on interfacial reactions. Current methods including hard‐template (nanocasting) method or thermal‐assisted conversion (TAC) still suffer from drawbacks such as cumbersome and environmentally unfriendly process, humidity sensitivity, or ill‐defined mesostructures. Herein, the study reports a facile synthesis of ordered mesoporous TMDs/carbon composites by direct organic–inorganic co‐assembly in dual solvent (DMF/H2O). The amphiphilic block copolymer polyethylene oxide‐b‐polystyrene (PEO‐b‐PS) is used as the organic template, and (NH4)2MoS4 or (NH4)2WS4 as the inorganic precursor. After solvent evaporation‐induced aggregation assembly and thermal treatments, it results in highly ordered mesoporous MoS2, WS2, and MoS2/WS2 with highly crystalline framework, high specific surface area (44‐91 m2 g−1) and large pore sizes (15–21 nm). Semiconductor gas sensors based on mesoporous TMDs exhibit extraordinary sensing performances toward NO2 at room temperature, including high sensitivity and ultrahigh selectivity, benefiting from its abundant adsorption sites for gas molecules, fast diffusion rate in well‐connected mesopores, and rich edge active sites. This work paves a facile way to develop novel ordered mesoporous TMDs‐based semiconductor materials for various applications.

Surface-engineered in-situ fibrillated thermoplastic polyurethane as toughening reinforcement for geopolymer-based mortar

Geopolymer composites often exhibit severe brittle failure when subjected to tensile and flexural loads, mainly owing to their inherently ceramic-like structure. Therefore, this study aims to overcome the previously mentioned weaknesses by introducing 2 wt% of surface-modified, in-situ fibrillated Co-PP (copolymer of polyethylene (PE) and polypropylene (PP))/thermoplastic polyurethane (TPU) blend to produce fiber-reinforced geopolymer mortars. The fiber-in-fiber Co-PP/TPU was first fabricated using spunbond, then functionalized using a mild, two-step, one-pot chemical surface modification process. A comprehensive and detailed study of the fibers' chemical structure, morphology, and mechanical properties has been conducted. As well as their impact on the geopolymer mortars' mechanical performances. Moreover, incorporating the modified fibers dramatically increased the flexural toughness and strength at failure of the composite, reaching up to 1600 % and 280 % compared to the control sample, respectively. Furthermore, the flexural modulus was improved by 2 folds. Additionally, the split tensile and compressive strength were improved by 84 % and 17 %, respectively. These findings and the SEM images of the fractured samples indicate the presence of several toughening mechanisms, associated with an improved matrix-fiber interface and an enhanced growth of geopolymer products around the fiber's surface.

Improvement of thermal, mechanical, and electromagnetic interference shielding properties of polyethylene nanocomposites by introducing non‐covalently modified carbon nanotube and reactive polyethylene copolymer

AbstractWe herein report the enhancement of thermal, electrical, electromagnetic interference (EMI) shielding, and mechanical performance of polyethylene (PE) nanocomposites by the introduction of non‐covalently modified multi‐walled carbon nanotube (MWCNT) and ethylene‐glycidyl methacrylate (EGMA) copolymer. For this purpose, benzylacetic acid‐functionalized MWCNT (BA‐M) is prepared by ball milling, and it is melt‐mixed with EGMA to prepare a masterbatch. The masterbatch is then melt‐compounded with neat PE to manufacture a series of PE/EGMA/BA‐M nanocomposites with 0.5–5 wt% MWCNTs. Electron microscopic and spectroscopic analyses confirm the successful fabrication of non‐covalently functionalized BA‐M, the uniform dispersity of MWCNTs in the PE matrix, and the chemical reactions between the carboxylic acid groups of BA‐M and the epoxy group of EGMA in the nanocomposites. Scanning calorimetric data reveals that BA‐M acts as an efficient nucleating agent for the crystallization of PE. The excellent dispersity and robust interfacial bonding of BA‐M in the PE matrix result in improved electrical and EMI shielding properties in PE/EGMA/BA‐M nanocomposites. Furthermore, the tensile strength, initial modulus, and impact strength of the nanocomposites gradually rise as the BA‐M content increases. Thus, the PE/EGMA/BA‐M nanocomposite containing 5 wt% MWCNT achieves excellent performance of EMI shielding effectiveness of ~14.7 dB/mm, tensile strength of ~34.5 MPa, initial modulus of ~295.7 MPa, and impact strength of ~539.9 J/m, which represent enhancements of ~265%, ~40%, ~82%, and ~452%, respectively, compared to pristine PE.Highlights Non‐covalently modified MWCNT (BA‐M) was prepared by facile ball milling. PE nanocomposites with BA‐M and EGMA were prepared by masterbatch melt‐mixing. Excellent dispersity and interfacial bonding of MWCNT in the PE matrix were attained. Tensile strength and initial modulus of the nanocomposites were highly improved. EMI shielding effectiveness of the nanocomposite with 5 wt% MWCNT was ~14.7 dB/mm.

Influence of PEG-PPG-PEG Block Copolymer Concentration and Coagulation Bath Temperature on the Structure Formation of Polyphenylsulfone Membranes.

The effect of amphiphilic block copolymer polyethylene glycol (PEG)-polypropylene glycol (PPG)-PEG concentration in the polyphenylsulfone (PPSU) casting solution and coagulation bath temperature (CBT) on the structure, separation, and antifouling performance of PPSU ultrafiltration membranes was studied for the first time. According to the phase diagram obtained, PPSU/PEG-PPG-PEG/N-methyl-2-pyrrolidone (NMP) systems are characterized by a narrow miscibility gap. It was found that 20 wt.% PPSU solutions in NMP with the addition of 5-15 wt.% of PEG-PPG-PEG block copolymer feature upper critical solution temperature, gel point, and lower critical solution temperature. Membrane composition and structure were studied by Fourier-transform infrared spectroscopy, scanning electron and atomic force microscopies, and water contact angle measurements. The addition of PEG-PPG-PPG to the PPSU casting solution was found to increase the hydrophilicity of the membrane surface (water contact angle decreased from 78° for the reference PPSU membrane down to 50° for 20 wt.%PPSU/15 wt.% PEG-PPG-PEG membrane). It was revealed that the pure water flux increased with the rise of CBT from 18-20 L·m-2·h-1 for the reference PPSU membrane up to 38-140 L·m-2·h-1 for 20 wt.% PPSU/10-15 wt.% PEG-PPG-PEG membranes. However, the opposite trend was observed for 20 wt.% PPSU/5-7 wt.% PEG-PPG-PEG membranes: pure water flux decreased with an increase in CBT. This is due to the differences in the mechanism of phase separation (non-solvent-induced phase separation (NIPS) or a combination of NIPS and temperature-induced phase separation (TIPS)). It was shown that 20 wt.% PPSU/10 wt.% PEG-PPG-PEG membranes were characterized by significantly higher antifouling performance (FRR-81-89%, DRr-26-32%, DRir-10-20%, DT-33-45%) during the ultrafiltration of bovine serum albumin solutions compared to the reference PPSU membrane prepared at different CBTs (FRR-29-38%, DRr-6-14%, DRir-74-89%, DT-88-94%).

Development of a Measurement System Using Infrared Spectroscopy-Attenuated Total Reflectance, Principal Component Analysis and Artificial Intelligence for the Safe Quantification of the Nucleating Agent Sorbitol in Food Packaging.

Sorbitol derivatives and other additives are commonly used in various products, such as packaging or food packaging, to improve their mechanical, physical, and optical properties. To accurately and precisely evaluate the efficacy of adding sorbitol-type nucleating agents to these articles, their quantitative determination is essential. This study systematically investigated the quantification of sorbitol-type nucleating agents in food packaging made from impact copolymers of polypropylene (PP) and polyethylene (PE) using attenuated total reflectance infrared spectroscopy (ATR-FTIR) together with analysis of principal components (PCA) and machine learning algorithms. The absorption spectra revealed characteristic bands corresponding to the C-O-C bond and hydroxyl groups attached to the cyclohexane ring of the molecular structure of sorbitol, providing crucial information for identifying and quantifying sorbitol derivatives. PCA analysis showed that with the selected FTIR spectrum range and only the first two components, 99.5% of the variance could be explained. The resulting score plot showed a clear pattern distinguishing different concentrations of the nucleating agent, affirming the predictability of concentrations based on an impact copolymer. The study then employed machine learning algorithms (NN, SVR) to establish prediction models, evaluating their quality using metrics such as RMSE, R2, and RMSECV. Hyperparameter optimization was performed, and SVR showed superior performance, achieving near-perfect predictions (R2 = 0.9999) with an RMSE of 0.100 for both calibration and prediction. The chosen SVR model features two hidden layers with 15 neurons each and uses the Adam algorithm, balanced precision, and computational efficiency. The innovative ATR-FTIR coupled SVR model presented a novel and rapid approach to accurately quantify sorbitol-type nucleating agents in polymer production processes for polymer research and in the analysis of nucleating agent derivatives. The analytical performance of this method surpassed traditional methods (PCR, NN).

Crosslinking of polyethylene with polysilsesquioxane via carbamate linkages: Synthesis, shape recovery, and reprocessing properties

AbstractIn this contribution, we reported the crosslinking of polyethylene (PE) with dynamic silyl ether bonds. First, polycyclooctene copolymers bearing hydroxyl groups were synthesized via the ring‐opening metathesis copolymerization of cyclooctene with 5‐norbornene‐2‐methanol. The hydroxy‐functionalized polycyclooctene copolymers were further hydrogenated into the corresponding hydroxy‐functionalized PE copolymers. The PE copolymers were allowed to react with 3‐isocyanatopropyltriethoxysilane to obtain the PE copolymers bearing triethoxysilane groups. By taking advantage of hydrolysis and condensation of triethoxysilane groups grafted onto PE chains, the PE copolymers were well crosslinked; polysilsesquioxane (PSSQ) segments behaved as the crosslinking linkages in the networks. Notably, the PE networks were reprocessable (or recyclable) while zinc trifluoromethanesulfonate [Zn(OTf)2] was incorporated. The reprocessing properties of the PE networks were quite dependent on the crosslinking densities. The reprocessing behavior of the networks is attributable to the introduction of two dynamic chemistries: (i) the metathesis of silyl ether bonds which was catalyzed with Zn(OTf)2 and (ii) transcarbamoylation of carbamates which was catalyzed with dibutyltin dilaurate. Owing to the crosslinking, the PE networks displayed excellent shape memory properties. For the shape memory networks, notably, the original shapes can be reprogrammed with the aid of the exchange of the dynamic covalent bonds introduced into the systems.

Microplastics in the Danube River and Its Main Tributaries—Ingestion by Freshwater Macroinvertebrates

This study was carried out at the Danube River and its tributaries during the Joint Danube Survey 4 (JDS4) expedition. Three freshwater benthic species were used to estimate the quantity of microplastics (MPs): Corbicula spp., Limnodrilus hoffmeisteri (Claparede, 1862), and Polypedilum nubeculosum (Meigen, 1804). Following the kick and sweep technique, individuals were sampled using a hand net or dredge. In order to estimate the number of MP particles/individual particles/g wet body mass, the body mass and total length of all specimens were measured. Alkaline (Corbicula spp. and L. hoffmaisteri) and enzymatic (P. nubeculosum) protocols were performed for tissue degradation. All samples were filtered through glass microfiber filters (mesh size 0.5 µm). The particles were photographed, measured, and counted. A total of 1904, 169, and 204 MPs were isolated from Corbicula spp., L. hoffmaisteri, and P. nubeculosum, respectively. To confirm the chemical composition of isolated MPs, a subsample of 46 particles of the fragmented particles from 14 sampling sites was analysed via µ-ATR-FTIR spectroscopy analysis. The particles were characterised as polycarbonate (PC), polyethylene terephthalate (PET), polypropylene–polyethylene copolymer (PP-PE), nylon (polyamide-PA) and cellophane, with the domination of PET.

The contamination of in situ archaeological remains: A pilot analysis of microplastics in sediment samples using μFTIR

BackgroundMicroplastics (MPs) are found in all environments: aquatic, airborne, and terrestrial. While their presence is not disputed, their potential impacts are not yet known. ObjectiveTo undertake a pilot analysis of MP contamination in archaeological sediment samples, taken in the late 1980s from two archaeological excavation sites in the historic city of York (UK) as well as contemporary sources close to the same sites, with respect to the presence (if any), levels, and characteristics of any particles identified. MethodsThis study analysed pre-digested sediment samples as follows: n = 3 from Queens Hotel (QH) site and n = 3 Wellington Row (WR) contemporary core-source, and n = 3 QH and n = 3 WR archival-source samples, alongside procedural controls (n = 8), using μFTIR spectroscopy (size limitation of 5 μm) to detect and characterise any MPs present. ResultsIn total, 66 MP particles consisting of 16 MP polymer types were identified across both site and contemporary/archived samples. The highest levels of MP particles, 20,588 MP/kg was identified at the lowest sample depth (∼7.35 m) at archived WR, 5910 MP/kg in the mid depth layer (∼5.85 m) at the contemporary QH site. Of the MPs detected in sediment samples overall, polytetrafluoroethylene (PTFE), polybutylene sulfone (PSU), and polypropylene: polyethylene (PE:PP) copolymer polymer types were most abundant; mainly fragmented and irregular shape. ConclusionsThis is believed to be the first evidence of MP contamination in archaeological sediment (or soil) samples with polymers and size ranges measured and while accounting for procedural blanks. These results support the phenomenon of transport of MPs within archaeological stratigraphy, and the characterisation of types, shapes and size ranges identified therein. Through contamination, MPs may compromise the scientific value of archaeological deposits, and environmental proxies suspended within significant sediment, and as such represent a new consideration in the dynamism of, as well as arguments for preserving, archaeological deposits in situ.

Role of dynamic surface tension of silicone polyether surfactant-based silicone coatings on protein adsorption: An insight on the ‘ambiguous’ interfacial properties of Fouling Release Coatings

Non-toxic antibiofouling coatings are currently developed to avoid the negative impacts of the settlement of (micro)organisms on any water immersed surfaces. In some industries such as microalgae culture, marine sensors or even contact lenses, in addition to the need for antibiofouling efficiency, transparency and non-toxicity are prerequisite surface properties. In this work, seven amphiphilic transparent antifouling coatings have been elaborated using silicone polyether copolymer surfactants mixed in a polydimethylsiloxane-based elastomer matrix. Average molar masses (1.3–11.7 kDa) and molar mass distributions of each surfactant were assessed by pulse-field gradient spin-echo (PGSE) diffusion NMR. Surface and bulk properties of the designed coatings were characterized by measuring their surface roughness (0.03–0.07 μm), Young's modulus (1.4–2.2 MPa) as well as their wetting behavior. Results obtained from different wetting techniques have shown that coatings had initially a low surface free energy (around 20 mJ/m2) and that their surface became amphiphilic in contact with water (from 21 to 42 mJ/m2). Fitting of water contact angle measurements with the so-called O'Brien-Paranjape dynamic surface tension (DST) model enabled the calculation of the surfactant's diffusivities within the PDMS elastomer matrix (ranging from 9.96 × 10−15 to 1.77 × 10−13 m2·s−1) while providing a comprehensive insight on the kinetic interfacial variation of the overall amphiphilic coating. Coatings with the highest rates of water contact angle variation have been shown to positively affect the bovine serum albumin (BSA) protein adsorption.

Obtaining a graft copolymer of polyethylene by electrodischarge synthesis

Obtaining a graft copolymer of polyethylene by electrodischarge synthesis

Investigation of the Properties of Polyethylene and Ethylene-Vinyl Acetate Copolymer Blends for 3D Printing Applications.

3D printing of polyolefins, such as polyethylene (PE) and polypropylene (PP), is of great practical interest due to the combination of high properties of these materials. However, the use of these materials in 3D printing is associated with many problems due to their high rate of crystallization, which causes shrinkage and warpage of the printed object. In this regard, blends of PE and ethylene-vinyl acetate copolymer (EVA) of various compositions were investigated for 3D printing. It was found that with an increase in the concentration of EVA, an increase in the pseudoplastic effect and amorphization of PE occurs. It has been shown that with an increase in the EVA content, the degree of crystallinity of PE decreases slightly (by 11% at a content of 80% EVA); however, a significant decrease in the rate of crystallization of PE is observed (by 87.5% at the same EVA concentration). It was found that PE and EVA are completely compatible in the amorphous phase and partially compatible in the crystalline phase, which leads to a slight decrease in the melting point of PE. The introduction of EVA also leads to a significant increase in impact strength: the maximum value is achieved at a 50/50 ratio, which is five times the value of the initial PE and two times the value of the initial EVA. At the same time, it was revealed that EVA leads to a gradual decrease in the elastic modulus and strength of PE, the change of which generally obeys the additivity rule. The resulting printing filaments are characterized by a certain ovality due to their shrinkage, which decreases with increasing EVA content and reaches a minimum value at a PE/EVA ratio of 30/70. This composition also demonstrates the lowest shrinkage of the printed sample and higher processability during printing.

Exploring the effect of different waste polypropylene matrix composites on service performance of modified asphalt using analytic hierarchy process

Using end-of-life polypropylene (PP) as additive to modify base asphalt has received rapid-growing attention. However, the low flexibility of waste PP results in undesired low-temperature property so as to limit its application. Accordingly, three waste PP matrix copolymers were analyzed in this study, including laboratory-made PP, ethylene-propylene-rubber (EPR) and polyethylene (PE) copolymer, commercial highimpact PP (HIPP) and fiber reinforced PP (FRPP). Moreover, their modifying effects were measured with respect to creep recovery, force-ductility curve, fatigue resistance and storage stability. The fluorescence micrograph (FM) was also analyzed to reveal the modification mechanism. Analytic hierarchy process (AHP) was employed to determine the optimum waste PP matrix composite and concentration. Test results showed that mingling waste PP with rubber, elastomer or fiber was attributed to enhance the toughness of corresponding modified asphalt at low temperature. Considering the overall properties of modified asphalts, the PP/EPR/PE a top priority and followed by HIPP and FRPP.

Получение полимерных композиционных материалов на основе наночастиц оксида цинка, синтезированных в плазменном разряде под действием ультразвука

Zinc oxide nanoparticles were synthesized and samples of films of polymer composite materials on their basis were obtained and studied. Zinc oxide nanoparticles were synthesized in a plasma discharge under the action of ultrasonic cavitation. To create composites with a homogeneous distribution of nanoparticles, solution technology was used, and then melt compounding technology. Composite materials based on a copolymer of polyethylene and vinyl acetate and zinc oxide nanoparticles were obtained, and not sonicated and sonicated nanoparticles were used. The obtained samples of composite materials were studied by X-ray phase analysis, X-ray fluorescence analysis and scanning electron microscopy. It was shown that there are differences between the samples: in the case of nanoparticles without ultrasonic treatment, the particles are more strongly aggregated inside the composite material and their average size is visually larger than in the case of a sample with nanoparticles subjected to ultrasonic treatment.

Structural design of a new XLPE Insulation material without cross-linking by-products and theoretical study on the reaction mechanism: An alternative to peroxide crosslinking

The cross-linked polyethylene (XLPE) is used in most advanced power cable insulation. The cross-linking byproducts based on typically dicumyl peroxide (DCP) cross-linking process increase the electrical conductivity of the insulation material. In order to remove the hazardous byproducts, an essential time-consuming and energy-consuming procedure is needed. Hence, a new XLPE production process without cross-linking by-products receives considerable attention. Here, the structural design of a new XLPE based insulation materials have been established. The cross-linking of epoxy and reactive functional groups between two polyethylene copolymers in situ through reactive compounding is an alternative to DCP crosslinking without cross-linker and byproducts. Theoretical investigation on the reaction process of covalent bonds forming and reaction mechanism is accomplished by density functional theory. Two reaction mechanisms, synergistic reaction and step-by-step reaction, are proposed. The reaction potential energy information of the twelve reaction channels at B3LYP/6–311 +G(d,p) level are obtained. The calculation results show that the epoxy and reactive functional groups between two poly-ethylene copolymers can react in situ and crosslink through the formation of covalent bond to realize the networking of XLPE. The reaction of maleic anhydride with H2O (or CH3OH) is more kinetically and thermodynamically favorable than that of maleimide. The reactivity of carboxylic acid functional group is stronger among three cross-linking reaction systems considered. The reaction Gibbs energy barrier heights of synergistic reaction are lower than that of step-by-step reaction by about 0.6 eV. The theoretical study on the reaction mechanism of epoxy and reactive functional groups between two polyethylene copolymers would be beneficial to avoid the forming of hazardous cross-linking byproducts, which is a promising method to design thermoplastic insulation materials for future power cables.

Theoretical study on the reaction mechanism of a new XLPE insulation material without cross‐linking byproducts: An alternative to peroxide cross‐linking

AbstractObjectiveDesign a new cross‐linked polyethylene (XLPE) insulation material without cross‐linking by‐products (an alternative to peroxide cross‐linking). Investigate the process of covalent bonds forming and reaction mechanism of four reaction systems.MethodTheoretical calculation of the reaction potential energy information of the eleven reaction channels is used density functional theory at B3LYP/6‐311+G(d,p) level.ResultsThe calculation results show that the epoxy and reactive functional groups between two poly‐ethylene copolymers can react in situ, form covalent bonds, and realize a network XLPE. This reaction process is cross‐linking byproduct‐free. The reactivity of carboxylic acid functional group is stronger among four reaction systems considered.DiscussionThe reaction Gibbs energy barriers of synergistic reaction are lower than that of step by step reaction. The reaction channel of attacking tertiary carbon site CH on epoxy is more kinetically favorable than that of attacking secondary carbon site CH2 on epoxy.ConclusionThe cross‐linking of epoxy and reactive functional groups between two polyethylene copolymers in situ would be beneficial to avoid forming cross‐linking byproducts of peroxide cross‐linking process, which is a promising method for design thermoplastic insulation materials for power cables.

Influence of plasticizer on the physical and mechanical properties of composites based on low density polyethylene and quartz

The influence of quartz (silicon dioxide) content on main physical and mechanical properties of composites based on low density polyethylene is considered. It is shown that the introduction of a compatibilizer – a copolymer of high-density polyethylene with maleic anhydride – into the composition improves the properties and compatibility of the mixed components. The use of synthesized polyethylene wax as a plasticizer made it possible to significantly improve the deformability of highly filled composites. The method of thermomechanical studies shows the patterns of change in thermomechanical curves in the temperature range of 20 –200°C, depending on the concentration of quartz in the presence of a plasticizer and a compatibilizer.