Pure Polypropylene Research Articles

Evaluation of the use and performance of natural filler based polypropylene/leonardite composites

The use of polypropylene (PP), which has reached a considerably high level in the last century and is one of the polymers whose properties have been investigated and studied in much more detail with the use of various additives, can be obtained as composite structures with the use of both inorganic and organic additives, and the desired properties can be modified according to the desired purpose. In this study, it was aimed to evaluate the behavior of leonardite, a rich source of humic acid, with PP composite structures, whose performance with thermoplastic materials has never been investigated before, although there are studies on its use in different sectors. To evaluate the effects of different ratios of leonardite additives on PP polymer, the composites were prepared with a twin screw extruder, and the test specimens were produced using an injection molding device. Spectroscopic, density, microscopic, mechanical (tensile, impact, flexural), thermal and color analyses of composites containing leonardite at 0, 0.5, 1, 3, 5, and 10 wt% were carried out. As the amount of leonardite in the composite increased, a slight increase was observed in the density values of the composites, with a maximum of 4.7%. In microstructure analysis, a homogeneous distribution of the filler was observed in composites reinforced up to 1 wt%, while agglomeration occurred at higher rates. While the highest tensile strength and flexural strength values were found for the 5 wt% leonardite filled composite, it was observed that these values increased from 31.8 MPa to 32.7 MPa and from 32.84 MPa to 37.84 MPa compared to the pure PP, respectively. The highest Izod impact strength value was determined for the 10 wt% leonardite filled composite and an increase in this value was obtained from 2.47 kJ/m2 to 2.85 kJ/m2. The nucleation effect explains the decrease in supercooling temperature observed in the thermal analysis results. Furthermore, an increase of the thermal stability of PP/leonardite composite structures was demonstrated. When the color analysis results were examined, it was seen that the leonardite additive caused the color of the composite to darken, as expected.

Corrosion-Resistant Polymer Composite Tubes with Enhanced Thermal Conductivity for Heat Exchangers

The heat transfer surfaces of heat exchangers are usually made of metals which may suffer from severe corrosion. When corrosive fluids are present, highly corrosion-resistant metals, graphite or ceramics are used, resulting in high costs. This study presents measured data on the thermophysical and mechanical properties of recently developed corrosion-resistant polymer composite tubes for use in heat exchangers. Extruded polymer composite tubes based on polypropylene or polyphenylene sulfide filled with graphite flakes were investigated. The anisotropic thermal conductivities of the polymer composite tubes were measured at various temperatures. The through-wall thermal conductivity of the tubes made of polypropylene filled with 50 vol.% graphite is increased by a factor of 30 compared to pure polypropylene, resulting in a thermal conductivity of 6.5 W/(m K) at 25 °C. The tubes composed of polyphenylene sulfide filled with 50 vol.% graphite have a through-wall thermal conductivity of 4.5 W/(m K) at 25 °C. The mechanical properties of the polymer composites were measured using tensile and flexural tests at different temperatures. The composite materials are more rigid and keep their mechanical properties up to a higher temperature level compared to the unfilled polymers. Surface roughness measurements show the very smooth and sealed surface of the composite tubes. The results contribute to establishing the viability of using polymer composites for heat exchanger applications with corrosive fluids.

Study the Effect of Adding Malic Anhydride and Carbon Fibers to the Mechanical and Morphology Properties of Polypropylene

Adding reinforcement materials like carbon fibers with maleic anhydride improves the strength of polypropylene. The present work aimed to study the effect of adding maleic anhydride and carbon fibers on the mechanical properties of polypropylene enhanced by presenting carbon fibers. Carbon fibers added at different ratios (0, 2, 4, 6, and 8) % and 1% of maleic anhydride were added to pure polypropylene. Standard tensile and impact test specimens were prepared per ASTM standards using an extruder technique. It was observed that increasing the carbon fiber content enhanced the tensile strength, modulus of elasticity, and hardness of polypropylene while the elongation decreased, but it enhanced after MAH addition. SEM and FTIR indicated good adhesion between fibers and polypropylene after adding maleic anhydride (MAH). UV tests showed that carbon fibers protect the composite material from the UV sunlight.

Efficient flame retardancy of polypropylene by cobalt ions doped phytate melamine synergized with expandable graphite

Maintaining a delicate balance between flame retardancy and amount of expandable graphite (EG) in flame retardant polypropylene (PP) is still a formidable challenge, primarily due to the lower flame-retardant efficiency of EG. In order to address this concern, a novel cobalt-doped nanosheet flame retardant (PAMA-Co) was fabricated by a hydrothermal method utilizing phytic acid (PA) and melamine (MA), exhibiting a promising potential in constructing synergistic EG flame retardant PP. Significantly, the incorporation of only 7 wt% PAMA-Co/23 wt% EG system raises the limiting oxygen index (LOI) of PP to 27.3% and UL-94 V0 level, which indicates the excellent synergistic flame-retardant efficiency of PAMA-Co. Furthermore, both the peak heat release rate (PHRR) and the peak smoke production rate (PSPR) of PP composites with 7 wt% PAMA-Co/23 wt% EG are substantially reduced, exhibiting an 81.6% lower PHRR and 87.8% PSPR compared to pure PP. The excellent flame-retardant efficiency is attributed to the following mechanisms: Gas-phase dilution, catalytic cross-linking charring effect, and the suppression of the EG "popcorn effect" of PAMA-Co. In summary, this work not only advances an understanding of flame-retardant mechanisms but also offers a practical, green strategy for enhancing the safety and utility of PP in various applications.

Simultaneous enhancement in mechanical properties and flame retardancy of reed charcoal/polypropylene composites by graphene oxide interfacial modification

Biochar/polypropylene composites (BPCs) have great potential in automobiles and building materials due to their ease of processing and light weight. However, the inferior interfacial bonding strength between biochar and polypropylene (PP) and flammability of PP often result in the weak mechanical properties and poor flame retardancy of BPCs, which limit the practical applications of BPCs. Herein, graphene oxide (GO) is used as an active interfacial modifier to prepare graphene-reed charcoal/polypropylene (G-RC/PP) composites. Benefiting from the mechanical interlocking effect formed by GO, the G-RC/PP composites exhibit higher tensile and flexural strengths. When 1 % of GO was added (relative to mass of RC), the tensile and flexural strengths were 22.84 MPa and 50.8 MPa, respectively, which are 16 % and 22.7 % higher than pure PP. Additionally, the barrier-adsorption-dilution synergetic effects of GO enhance both the thermal stability and flame retardance of the composites. The total heat release rate of G-RC/PP composites is reduced by 71.6 % compared to RC/PP when GO was added at 1 %, resulting in a substantial reduction in fire hazards. This study offers a fresh perspective on the development of biochar/plastic composites with exceptional mechanical properties and high fire safety towards extensive applications as automotive parts and building structures.

Forming performance and environmental impact of bamboo fiber reinforced polypropylene composites based on injection molding process for automobiles

AbstractTo explore the potential application of plant fiber reinforced composites for automotive component applications, this study prepared bamboo fiber (BF)/nano‐talc/polypropylene (PP) composites based on the injection molding process, comprehensively evaluated the effect of reinforcement materials on the forming properties of composites, including thermal performance, mechanical properties, water absorption, etc. Furthermore, taking a certain automotive injection molded interior part as the object, a life‐cycle assessment from production to the gate was conducted based on the real energy and material consumption during the composite preparation process. The results indicate that adding BF and talc powder increased the thermal stability, density, hardness, viscosity, and crystallinity of the composites while reducing the water contact angle on the surface. Surface‐modified BF and PP showed good compatibility. Talc powder exhibited good dispersibility in PP, and the synergistic effect of BF and talc powder effectively enhanced the composite performance. The tensile, flexural, and impact strength of the composites were improved by 40.64%, 51.48%, and 66.51%, respectively, compared with pure PP. The modulus of the composite increased nearly 2 times compared with pure PP. Additionally, the composite demonstrated good friction and wear properties. The environmental impact of the BF composite manufacturing process was significantly higher than that of pure PP. The substantial consumption of electricity, chemicals, and water resources in the extraction and modification processes of BF were the main factors. The findings of this study contribute to achieving green, high‐performance BF composite manufacturing and the expansion of its applications.Highlights Composites have a higher environmental impact compared to PP. BF and talc can synergistically enhance the performance of composites. BF shows good compatibility with PP. Composites exhibit good friction and wear characteristics.

Recovering Valuable Chemicals from Polypropylene Waste via a Mild Catalyst-Free Hydrothermal Process.

Waste polypropylene (PP) presents a significant environmental challenge, owing to its refractory nature and inert C-C backbone. In this study, we introduce a practical chemical recovery strategy from PP waste using a mild catalyst-free hydrothermal treatment (HT). The treatment converts 64.1% of the processed PP into dissolved organic products within 2 h in an air atmosphere at 160 °C. Higher temperatures increase the PP conversion efficiency. Distinct electron absorption and emission characteristics of the products are identified by spectral analysis. Fourier transform-ion cyclotron resonance-mass spectrometry (FT-ICR-MS) reveals the oxidative cracking of PP into shorter-chain homologues (10-50 carbon atoms) containing carboxylic and carbonyl groups. Density functional theory (DFT) calculations support a reaction pathway involving thermal C-H oxidation at the tertiary carbon sites in the polymer chain. The addition of 1% H2O2 further enhances the oxidation reaction to produce valuable short-chain acetic acids, enabling gram-scale recycling of both pure PP and disposable surgical masks from the real world. Techno-economic analysis (TEA) and environmental life cycle costing (E-LCC) analysis suggest that this hydrothermal oxidation recovery technology is financially viable, which shows significant potential in tackling the ongoing plastic pollution crisis and advancing plastic treatment methodologies toward a circular economy paradigm.

EPR STUDY OF THE EFFECT OF γ-IRRADIATION ON POLYPROPYLENE/(CdS+ZnS) COMPOSITES

A composite materials with various fillers prepared by adding cadmium sulfide (CdS) and zinc sulfide (ZnS) particles to a polypropylene (PP) matrix and irradiated with different doses of γ-rays were studied by the electron paramagnetic resonance method (EPR). The EPR spectra were investigated, and the nature of the free radicals generated from irradiation was identified. It has been shown that the concentration of radicals in the composites is much lower than in pure PP. The presence of the filler counteracts the effect of γ-rays on the formation of radicals. This result shows that the radiation resistance of the composites is higher.

Effect of antibacterial masterbatches selection on the crystal structure and properties of nanosilver composite materials

AbstractThe distribution of nanosilver in composite materials with two different matrices is related to the selection of antibacterial masterbatches, which has a profound impact on the antibacterial effectiveness of the composite materials. This study utilized ethylene‐vinyl acetate (EVA) and polypropylene (PP) as base materials to fabricate two types of nanosilver composite materials (C1‐EVA/PP and C2‐EVA/PPP) employing varying methods of antimicrobial masterbatches incorporation. Additionally, EVA‐Ag and PP‐Ag nanosilver composite materials were fabricated via melt blending, along with corresponding neat materials and blends (EVA, PP, and C0‐EVA/PP) for comparison. The study results indicate that the addition of nanosilver did not affect the functional groups of either the neat materials and the EVA/PP blends. SEM analysis revealed that nanosilver was dispersed unevenly in the C1‐EVA/PP substrate, while it was more uniformly distributed in the C2‐EVA/PP substrate. In the antibacterial test, the antibacterial rate of C2‐EVA/PP was higher than that of C1‐EVA/PP (56.0% vs. 40.0%). However, all silver‐containing composite materials did not exhibit antibacterial properties in the agar diffusion test. Additionally, nanosilver exhibited an induced crystallization effect on the PP phase of the C2‐EVA/PP composite material, increasing its Tc2 by 0.8°C. Compared with pure PP, the long period of PP‐Ag increased by 0.7 nm, and its impact resistance improved by 13.8%. By comparison, the long period of EVA‐Ag composite materials increased by only 0.2 nm compared to pure EVA. Both C1‐EVA/PP and C2‐EVA/PP composite materials showed 0.3 nm increase in long period compared to C0‐EVA/PP, with their impact resistance improving by 3.1% and 10.3%, respectively, compared to C0‐EVA/PP. The introduction of nanosilver increased the storage modulus, loss modulus, and apparent viscosity of EVA/PP blends. Optical performance analysis shows that nanosilver increases the internal haze of C1‐EVA/PPP by 60% while reducing the transmittance by 0.3%. The effect of nanosilver on the optical properties of C2‐EVA/PPP composites is relatively small. Therefore, this study provides theoretical guidance for the selection of processing methods for dual‐phase antibacterial materials.Highlights Different antibacterial masterbatch impacts silver distribution in composites. The addition of nanosilver can improve the impact performance of materials. Two process methods were used to prepare low‐silver content composite materials. The antibacterial rate of C2‐EVA/PP is higher than C1‐EVA/PP (56% vs. 40%). This study guides the processing methods for dual‐phase antibacterial materials.

Synthesis of graphene oxide/layered double hydroxides hybrids via co-precipitation and their polypropylene composites

A series of hybrid particles consisting of graphene oxide and magnesium–aluminium-layered double hydroxides (GO/Mg–Al-LDHs) were prepared by the co-precipitation method and then modified by allyltrimethoxysilane (ATMS). X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectra, Raman spectra and field emission scanning electron microscope (FESEM) micrograph results showed the modified GO/Mg–Al-LDHs were synthesised with a smaller particle size and better dispersion. The polypropylene (PP) composites were prepared via the reactive extrusion method, and the effects of GO content in hybrids on the mechanical properties, processability, thermal stability, flame retardation, melting and crystallisation behaviour of composites were investigated in detail. The comprehensive properties of composites containing GO/Mg–Al-LDHs were excellent compared to those of Mg–Al-LDHs under the same filler concentration. Compared with pure PP, 20 wt-% of GO/Mg–Al-LDHs-2.5 increased the limiting oxygen index (LOI) value of composites from 16.4% to 28.8% with a V-0 level of U-94 testing and decreased the heat release rate (HRR) and total heat release (THR) values from 1206.4 kW/m2 and 133.9 MJ/m2 to 146.9 kW/m2 and 69.6 MJ/m2. Meanwhile, the tensile, impact strength and elongation at break were 36.2 MPa, 3.0 kJ/m2 and 68.6%, respectively. This work provided an effective strategy for enhancing the dispersion and comprehensive properties of GO/LDHs-based composites.

Synthesis and Flame Retardant Behavior of Phosphorous- and Nitrogen-Containing Copolymer and Its Application in Polypropylene.

In this study, a 4-(hydroxymethyl)-2,6,7-trioxa-1-phosphabicyclo[2.2.2]octane 1-oxide (PEPA)-functionalized acrylate monomer, PEPAA, is designed and utilized for the synthesis of macromolecular flame retardants poly(PEPAA-co-AM) with varying PEPAA/AM ratio through copolymerization with acrylamide (AM). The poly(PEPAA-co-AM) is then incorporated into polypropylene (PP) to prepare PP/poly(PEPAA-co-AM) composites. The flame retardant effect of poly(PEPAA-co-AM) on PP is investigated using cone calorimetric test (CCT), and compared with that of PEPAA homopolymer (P-PEPAA), AM homopolymer (PAM), and blends of P-PEPAA/PAM. The results demonstrate that, in comparison with P-PEPAA, PAM, and blends of P-PEPAA/PAM, the incorporation of poly(PEPAA-co-AM) significantly enhances the flame retardancy of PP. Notably, the best flame retardancy is achieved when the ratio of PEPAA/AM copolymerization in poly(PEPAA-co-AM) is 2/8. The morphology and composition of residual chars from combustion are analyzed using SEM-EDS while the residual graphitization degree is examined through Raman spectroscopy. Additionally, TG-FTIR-MS is utilized to investigate the pyrolysis products in gas phase during thermal decomposition of poly(PEPAA-co-AM). Based on these experimental results, a flame retardant mechanism for poly(PEPAA-co-AM) is proposed. The PP/poly(PEPAA-co-AM) composites not only retain the excellent processing properties of pure PP but also exhibit enhanced mechanical properties.

Research on mechanics and acoustic properties of Jute fiber composite material

In this study, the loss of quality from the oxidative thermal decomposition of jute fiber was explored during the production of reinforced composite materials. Amino silicone oil was used to modify jute fiber, which was then subjected to thermogravimetric analysis. The modified fiber's thermal decomposition temperature was found to be 271 °C, enhancing the composite's thermal stability. The study also investigated how different jute fiber content affected the mechanical and sound absorption properties of composite materials. Results showed that jute fiber composites had better mechanical properties than pure polypropylene materials, and the average sound absorption coefficient of jute polypropylene composites increased with fiber content. Adding jute fiber to polypropylene effectively improved the sound absorption and noise reduction performance of the material. The average sound absorption coefficient of the composite material at a mass content of 20 wt% was 120 % higher than that of the polypropylene matrix material.

The effect of extraction conditions on the chemical profile of obtained raw poplar propolis extract

Various conditions of extraction were applied to obtain active extracts of raw poplar-type propolis. The extraction efficiency of traditional maceration was evaluated in terms of used solvent: ethanol (70 and 96% v/v), acetone (pure and 70%), propylene glycol, glycerol (50%), water and water with extraction modifiers: PEG 400 and lecithin. For obtained extracts, the total amounts of extracted phenolics and flavonoids as well as antioxidant activity were compared. For the most active extracts, the profile of volatile organic compounds with the use of GC × GC–MS and selected polyphenols content by HPLC–DAD was compared. To increase the activity of water propolis, extract ultrasound and microwave-assisted extraction were applied and obtained water extracts were compared regarding the main polyphenolic compounds content quantified by HPLC method. The recovery of 70% ethanolic extraction and the effect of the extension of extraction time were also examined by the HPTLC method. Based on conducted analyses, 70% ethanolic extract was found as the most aromatic and bioactive, followed by pure acetone and polypropylene glycol extracts. Compared to the classic maceration, water extraction assisted by microwaves and ultrasounds did not provide a higher extraction yield. In the case of 70% ethanolic extraction, the 5-day duration is recommended which allows to recovery of close to 80% of bioactive components of raw propolis.

The Mechanical and Physical Properties of 3D Printing Filament made from Recycled Polypropylene and Ground Tyre Rubber Treated with Alkali

When molten, used vehicle tyres are unable to decompose or be recycled. Despite global efforts to find new uses for these materials, many worn tyres are still dumped in landfills. Therefore, this study proposes using ground tyre rubber (GTR) as a fill material for recycled polypropylene 3D printing filament. The filament composite’s physical and mechanical properties will be assessed in this investigation. GTR is expected to give the filament elastic characteristics, which could lead to rubber-like filaments. This study filled recycled polypropylene (rPP) polymer matrix composites with GTR to make filament. The mechanical and physical properties of a 3D-printed specimen made from rPP and GTR filament with varying compositions were analysed. Compared to pure rPP, rPP/GTR samples with 3 wt% GTR had a maximum tensile strength of 716.76 MPa. The flexural test findings showed that rPP/GTR with 3 wt% GTR had the highest flexural strength at 80.53 MPa, followed by rPP/1 wt% GTR at 65.38 MPa. In physical tests, the rPP/GTR at 5 wt% GTR had the highest water absorption at 5.41 %, and the wt% of GTR connected directly with water absorption. This study has shown that affordable, environmentally friendly rPP/GTR filaments can be developed with less amount of GTR content (3 wt%) and used for 3D printing applications, helping to lessen the impact of plastic and waste while having valuable mechanical and physical properties that are comparable to those of the pure polypropylene material produced.

Biochar for sustainable additive manufacturing: Thermal, mechanical, electrical, and rheological responses of polypropylene-biochar composites

The utilization of eco-friendly reinforcing materials and the fabrication of sustainable composites with enhanced mechanical and electrical properties are a subject of great scientific interest. Such research is aiming to be applied in a variety of industrial applications. In this study, polypropylene (PP) was used as a matrix material and combined with biochar (BC) as a filler at different loadings (2.0, 4.0, 6.0, 8.0, and 10.0 wt %) to produce reinforced composites. Biochar was produced from olive tree prunings. Additively manufactured specimens underwent a variety of tests (fourteen in total) regarding their thermal, structural, mechanical, morphological, and electrical properties. The mechanical properties of the PP were improved by the addition of 4.0 wt % biochar, as the tensile strength and modulus of elasticity, presented a 28.4 % and 24.3 % increase compared to that of pure PP. Overall, the 6 wt % was the optimum loading considering all the tests conducted. The thermal stability of the PP/BC composites was significantly improved compared to that of pure PP. At a filler loading of 8.0 wt %, the dc-conductivity of PP/biochar composite increased by more than 9 orders of magnitude, suggesting the existence of a percolation threshold, above which the polymer composite switches from insulating behavior to a conductive state. Overall, biochar addition had a positive impact on all measured quantities and proved to be an eco-friendly material suitable for use in various applications of additive manufacturing (AM).

Precision control and parameter optimization in screw extrusion 3D printing of polypropylene materials

Fused Deposition Modeling (FDM), a widely-utilized additive manufacturing (AM) technology, has found significant favor among automotive manufacturers. Polypropylene (PP) compound is extensively employed in the production of automotive parts due to its superior mechanical properties and formability. However, aiming at the problem of poor dimensional accuracy of pure PP parts, the quality of products can be enhanced by optimizing the combination of processing parameters. In this paper, the dimensional accuracy of 3D-printed components made from pure PP material is investigated. Key influencing factors such as infill percentage, infill pattern, layer thickness, and extrusion temperature are considered. To gain a deeper understanding, fluid simulation is conducted, and mathematical models are established to correlate processing parameters with dimensional accuracy. Furthermore, the Taguchi's experiments are designed and the experimental data are subjected to rigorous Signal-to-Noise ratio and ANOVA analyses. Within the experimental range, the lower extrusion temperature, infill percentage and layer thickness yield the best dimensional accuracy. Considering the influence factors of X, Y and Z directions, the optimal processing parameters for PP prints using screw extrusion 3D printers are determined as follows: an extrusion temperature of 210 °C, an infill percentage of 40 %, a layer thickness of 0.3 mm, and a concentric circle infill pattern. This study provides reference value for the subsequent improvement of the dimensional accuracy of the printed parts.

Radiolysis of composite polypropylene/hemp fibers

Abstract This paper presents the results of the research on the effects of ionizing radiation on the properties of a composite material consisting of polypropylene (PP) and hemp fibers (HFs). The radiolysis effects were investigated for the composites having HF contents in the amounts of 10, 20, 30, and 40% by weight, as well as for pure PP. Particular attention was paid to the protective effects the aromatic compounds contained in the HF had on the radiolysis of PP/HF composites. This phenomenon may explain the deviations that the irradiated composites displayed upon the addition of HFs and their dependency on the HF content. Both the granules and the standardized composite specimens were subjected to radiation treatment. The gas chromatography (GC) technique was employed to determine the yield of radiolytically generated hydrogen (GH2) and absorbed oxygen (GO2). The oxidation phenomenon was studied during irradiation, 24 h after irradiation, and after a 40-day aging period at room temperature. Changes in the melt flow rate (MFR) and the mechanical properties were also determined. It was described how the radiation treatment of the investigated composites accelerates their degradation. It was found that this effect applies to both HF and PP. It was also demonstrated that PP not only does not enhance the resistance of HF to oxidation but, on the contrary, accelerates the processes of their post-radiation degradation. It was further observed that the phenomenon of postradiation degradation can be controlled by changing the PP content in the composite, as well as the amount of aromatic compounds present in the HF. The amount of the absorbed dose allows us to control the degradation time of the PP/HF composites. This applies in particular to the chain oxidation of the PP matrix triggered by the ionizing radiation. It was also found that composites based on PP and natural fibers susceptible to radiation degradation may have significant implications for the use of easily degradable polymer materials in the environment.

Preparation and properties of PP/SEBS foam materials

In this study, styrene-ethylene-butene-styrene block copolymer (SEBS) is blended with polypropylene (PP) to improve the melt strength of PP. Azodicarbonamide (AC) is used as a chemical foaming agent to prepare PP foaming materials with good mechanical properties by moulding foaming. The melt strength of the material, the content of the nucleating agent and the concentration of the foaming agent will affect the foaming effect of the material. Orthogonal optimization experiments are designed for these three factors to explore the best ratio of foaming materials. The results show that when PP:SEBS = 85:15, the addition amount of nano-SiO2 is 3%, and the content of AC foaming agent is 5%, the cell structure of the foaming material is the best. The cell structure is observed by SEM,the average cell diameter is reduced to 45.73 μm, and the cell density is increased to 4.12 × 106 cells cm−3. The apparent density of the material is measured to be 0.62 g cm−3, which is 32% lower than that of pure PP (0.91 g·cm−3). The tensile strength of PP/SEBS foamed composites is lower than that of pure PP and pure PP foamed materials, but its elongation at break is 124.3% higher than that of pure PP, and 238.8% higher than that of pure PP foamed materials. The bending strength of PP/SEBS foamed material is lower than that of pure PP and pure PP foamed material. The impact strength of PP/SEBS is only 8.4 % lower than that of pure PP, and 60.8 % higher than that of pure PP foamed material.

Assessment of properties of bamboo fiber and EPDM reinforced polypropylene microcellular foam composites

Plant fiber reinforced composite has broad industrial application prospects, and has the trend of gradually replacing traditional materials, but there are also problems such as not obvious advantages of lightweight and poor toughness. In this paper, alkali modified bamboo fiber reinforced polypropylene (BF/PP) composite was prepared by supercritical foam injection molding. The effect of fiber content on the formability of BF/PP composite was studied. Furthermore, the strength and toughness of BF/PP composites were balanced by blending Ethylene Propylene Diene Monomer (EPDM) elastomers with different content under the optimal fiber content of 20 %. The physical and mechanical properties of BF/PP composites were studied. The results showed that the addition of bamboo fiber improved the structure of the cell and significantly enhanced the mechanical properties of the composite. The addition of elastomer EPDM effectively alleviates the problem of poor toughness and brittle fracture of bamboo fiber composites. The foam material density decreased by about 15 %, the addition of bamboo fiber brought the maximum 57.37 % tensile strength and 79.96 % flexural strength improvement to the polypropylene matrix. When the EPDM content was 10 %, the foaming effect of the material was the best, and the impact toughness increased by 34.42 % compared with pure polypropylene. This study expands the application prospect of the bamboo fiber reinforced polypropylene microcellular foam materials.

The synthesis of a novel polymer‐type antistatic agent and its effect on the properties of polypropylene

AbstractIn this paper, a novel polymeric antistatic agent, TMQ, with excellent antistatic properties, low cost, and good compatibility with polypropylene (PP), was prepared from isopentenyl polyoxyethylene ether (TPEG), maleic anhydride (MAH) and homemade quaternary ammonium salt (QAS). The structure is characterized using FTIR and 1H NMR. How the addition of TMQ and the molar ratio of TPEG, QAS, and MAH affect the antistatic, mechanical, and crystalline properties of PP are investigated. The results show that as the feed ratio of TPEG, MAH and QAS is TPEG:MAH:QAS = 1:8:8, the modified PP displays the best overall performances. Further exploring finds out when TMQ is added at 15 wt%, the surface resistivity of PP reduces to 6.78 × 109 Ω/sq and the volume resistivity of PP reduces to 7.9 × 109 Ω cm−1, the notched impact strength and melt index improve by 357% and 991%, respectively, while the tensile strength decreases by 38.6% compared with that of pure PP. Besides, the crystal study shows after TMQ is added, the crystallinity of PP reduces, the melt peak temperature remains essentially unchanged, and the crystallization peak temperature increases slightly. The material has excellent antistatic resistance to washing and durability, and the changes in relative humidity have little effect on its antistatic properties.