Random Polypropylene Research Articles

Influence of Silica Nanoparticles on the Physical Properties of Random Polypropylene

Influence of Silica Nanoparticles on the Physical Properties of Random Polypropylene

Defining the Effect of a Polymeric Compatibilizer on the Properties of Random Polypropylene/Glass Fibre Composites

Random polypropylene composites reinforced with short glass fibres have been successfully fabricated by melt-mixing. Polypropylene grafted with maleic anhydride (PP-g-MA) was added to the composites, which was expected to act as a compatibilizer and greatly limit the negative effects known to arise from the feeble polymer matrix/glass fibre interfaces. The effect of compatibilizer concentration on the structural, mechanical and thermal behaviour of the composites has been investigated. The results revealed an improvement of the glass fibre/matrix interaction upon the addition of the compatibilizer, which resulted in enhancing the overall material stiffness and the ability of the matrix to store energy. In particular, the lowering of the glass transition and the investigation of the fracture surfaces of the composites confirmed the improved PPR/fibre adhesion. Examination of the tensile elongation indicated the improvement of the Young’s modulus and yield strength with the addition of PP-g-MA, while the storage modulus was also shown to be significantly increased. These results confirmed the versatility and efficiency of the approach presented in this work to improve the thermomechanical properties and sustainability of PPR and promote its usage in industrial applications and commercial manufacturing.

Investigation of Crystallization, Morphology, and Mechanical Properties of Polypropylene/Polypropylene-Polyethylene Block Copolymer Blends.

Polyethylene (PE)-based elastomers are the ideal choice for enhancing the compatibility of polypropylene/polyethylene (PP/PE) blends and improving the mechanical properties of PP-based materials. However, the issue of blend systems lies in the interplay between the crystallization processes. Therefore, we investigated the crystallization behavior during the cooling process of a new generation of PP/PE block copolymers (PP-b-PE) and random polypropylene (PPR, a copolymer of propylene and a small amount of ethylene or an alpha-olefin) blends using in-situ X-ray diffraction/scattering and differential scanning calorimetry (DSC) techniques. We also conducted mechanical performance tests on PPR/PP-b-PE blends at room temperature and low temperature (-5 °C). The results indicate that during the cooling process, the PP phase of PP-b-PE will follow the PPR to crystallize in advance and form a eutectic mixture, thereby enhancing the compatibility of PP/PE. Moreover, the PPR/PP-b-PE blend will form stable β-(300) crystals with excellent mechanical properties. Due to the improved compatibility of PP/PE with PP-b-PE, PE crystals are dispersed within PP crystals, providing bonding that improves the toughness of PPR under the low stiffness failure conditions of PPR/PP-b-PE blends, thereby enhancing their impact performance at low and room temperatures. This research has great significance for both recycling waste plastics and enhancing the low-temperature toughness of PPR.

Design of Clean Water Booster Pump for High-Rise Buildings

A sanitary system is a supporting component designed to meet the clean water requirements of a building, primarily for sanitation activities. The average sanitary equipment used typically requires a shower pressure of ±1 Bar. However, the shower pressure can be significantly affected by factors such as the distance from the top tank and the building's layout, considering only the pressure due to gravity. To address inadequate shower pressure, an auxiliary pump known as a booster pump is necessary. The need for a booster pump is determined by the cumulative demand from plumbing equipment, where the total capacity required is 6057 liters/hour. To address this demand, the system employs two pump units, each with a capacity of 3 m3/hour. The distribution pipes utilized in the system adhere to established standards and are made of random polypropylene with a diameter of 2 inches and a flow rate of 0.005889 m3/second. The overall head loss resulting from this installation amounts to 31.62 meters. To accommodate the booster system, a pressure tank with a capacity of 67 liters is employed. The minimum working pressure required for the pumps is 1.8 Bar.

Thermomechanical Characterization of E‐Glass Fiber Reinforced Random Polypropylene

AbstractThe thermomechanical properties of short glass fiber (GF) reinforced polypropylene random copolymer (PPR) composites are investigated. Four composites with different fiber content, namely 10, 15, 20, and 30 wt%, are prepared using melting mixing. For fibers up to 15 wt% the composites exhibit enhanced thermal stability as compared to the random polypropylene. The use of fibers also improve the mechanical strength of the matrix. In particular, PPR/GF30% demonstrates the highest Young modulus, yield strength, and storage modulus values, while PPR/GF10% has the best ductility among the composites. Incorporation of 10 wt% fibers also increases the yield strength and storage modulus of the PPR matrix by approximately 1.6 and 1.2 (for temperatures higher than 60°C) times, respectively. These results suggest that GF reinforced PPR is a composite suitable for advanced technological applications.

Thermal Deformation Properties of Dynamically Vulcanized Thermoplastic Elastomers Based on Random Polypropylene and Nitrile Butadiene Rubber

Thermal Deformation Properties of Dynamically Vulcanized Thermoplastic Elastomers Based on Random Polypropylene and Nitrile Butadiene Rubber

Mechanism and kinetic regularities of crystallization of nanocomposites based on bentonite and polymer mixtures of random polypropylene with butadiene nitrile rubber

The paper presents the results of a study of the dilatometric properties of thermoplastic elastomer nanocomposites based on mixtures of random polypropylene, nitrile butadiene rubber, a compatibilizer - copolymer of polypropylene with maleic anhydride. Nanosized bentonite particles were used as a filler. The concentration of bentonite nanoparticles was varied in the range of 1.0-20 wt %. The values of the free and occupied specific volumes of nanocomposites were determined depending on the temperature and concentration of bentonite. The mechanism and kinetic regularities of the crystallization process of nanocomposites are established.

Reaction extrusion of dynamically vulcanized nanocomposites based on thermoelastoplasts. Problems and solutions

A set of studies on the reaction extrusion of dynamically vulcanized nanocomposites based on bentonite and mixtures of random polypropylene with various brands of nitrile butadiene rubber was carried out. The influence of the temperature and pressure of the extrusion, the speed of the screw, the time of passage of the polymer mass through the material cylinder, as well as the compatibilizer, the type and concentration of the crosslinking agent on the main physicomechanical properties of dynamically vulcanized nanocomposites is established.

Fibre length and loading impact on the properties of glass fibre reinforced polypropylene random composites

Polypropylene composites have emerged as alternative materials for a wide range of applications requiring advanced mechanical and thermal properties including automotive and structural engineering. The choice of suitable polypropylene reinforcing agent enables higher flexibility, lightweight, mechanical strength and low production cost. This paper reports on the fabrication of short glass fibre reinforced random polypropylene by melt mixing. The mechanical and thermal properties of the random polypropylene/E-glass fibre composites exhibited a strong dependence on the fibre size varying from 1 mm to 0.3 mm and the various fibre contents, namely 10, 15, 20 and 30 wt%. Activation energy analysis suggested hindering of crystallization due to the presence of the fibres. However, a maximum yield strength of 29.4 MPa was measured for the 10 wt% fibre reinforced composites with an average fibre length of 1 mm. Furthermore, use of shorter fibres (average length of 0.3 mm) and a filler loading of 10 wt% resulted in a maximum elongation at break of 654%. Enhanced stiffness was also observed for fibre content up to 15%. These results suggest that the use of short glass fibres will allow the development of cost-effective and robust polypropylene composites adequate for a wide range of modern applications.

Термодеформационные свойства динамически вулканизованных термоэластопластов на основе рандом полипропилена и бутадиен-нитрильного каучука

The paper presents the results of a study of the thermodefomational characteristics of dynamically vulcanized thermoplastic elastomers based on random polypropylene and nitrile butadiene rubber (SKN). In order to improve the compatibility of polymer mixtures, Exxelor PO1200, a grafted copolymer of polypropylene with maleic anhydride, was used as a compatibilizer. The concentration of maleic anhydride in the composition of the grafted copolymer was 3.0 wt. %. It was shown that as a result of the loading of the compatibilizer, it seemed possible to improve the compatibility of bipolar mixtures, in which there was no separation between the components of the mixture. It was found that with the load of 30 wt. % SKN-18, as well as 40 wt. % SKN-26 or SKN-40 into the composition of random polypropylene, the polymer composition exhibits the properties of thermoplastic elastomers, as a result of which plastic deformation is replaced by a highly elastic characteristic for rubbers. The temperature regions of the solid, highly elastic, and viscous flowing states are determined. In order to give polymer blends greater elasticity, they were vulcanized using crosslinking agents such as dicumyl peroxide and sulfur. It is shown how, in the process of increasing the concentration of dicumyl peroxide from 0.25 to 1.0 wt. %, the thermomechanical properties of dynamically vulcanized thermoplastic elastomers significantly change. It was found that with the introduction of dicumyl peroxide in an amount equal to 1.0 wt. %, the melt flowability of vulcanized materials almost completely lose their ability to flow, and pass from a highly elastic state to a glassy one. With the load of sulfur in an amount of 1.0 to 10 wt. %, the melt flowability of the vulcanized thermoplastic elastomers is preserved.

Improved mode Ⅰ interlaminar fracture toughness of random polypropylene composite laminate via multiscale reinforcing formed by introducing functional nanofibrillated cellulose

Interface engineering and phase engineering of composites offer a promising route to rationally tune the interlaminar toughness of laminates, as high toughness plays an important role in preventing interlaminar failure and ensuring the safety of components. Herein, unlike the previous melt-mixing process, we coated the second reinforcement TONFC (TEMPO-oxidized nanofibrillated cellulose) on the surface of the main reinforcement (continuous glass fiber) by sol impregnation, and successfully prepared the commingled yarn random polypropylene (PPR) composite laminate with high interlaminar fracture toughness. The surface groups of each raw material of the composite system before and after the reaction were characterized and thereby obtaining the interface strengthening mechanism. Besides, the heterogeneous nucleation effect of TONFC and the mechanism of inducing ꞵ-phase formation were revealed by analysis of crystallization behavior and crystal structure. Further, through a double cantilever beam (DCB) test and morphology analysis, the effect mechanism of the addition of TONFC on the interlaminar crack propagation of PPR composite laminate was explored. This work provides a rapid and efficient avenue for the interlaminar modification of commingled yarn composites.

The effect of initiator, polyfunctional monomer and polybutene-1 resin on the long chain branching of random polypropylene copolymer via reactive extruder

ABSTRACT Polypropylene random copolymer (PPR) and polybutene-1(PB-1) are blended and long-chain branched (LCB) in the reactive extruder. The optimum amount of PB-1 resin, peroxide (DCP) and trimethylolpropane triacrylate (TMPTMA) for long-chain branching of PPR and probe topology formed by the branches were investigated. Fourier transformed infrared spectroscopy (FTIR) used to measure the branching degree and efficiency as well as obtaining TMPTMA grafts on PPR. Oscillatory shear rheological properties including complex viscosity, storage modulus, loss tangent, and uniaxial elongational rheometry were studied to differentiate the LCB-PPR from unmodified PPR with almost similar molecular weight samples. The LCB structure modified samples with TMPTMA and DCP, prominent higher zero-shear viscosity, longer relaxation time and pronounced strain-hardening behavior. It was found that different amount of DCP and TMPTMA can affect strain-hardening behavior and topology of branches and subsequently the foaming ability. PB-1 resin found to have a positive effect because of more sensibility to β-scission degradation and mobilizing effects. The optimization of PB-1 for the highest zero-shear viscosity, shear, and uniaxial rheological behavior is achieved at 10 wt% PB-1, while 0.08% of DCP and 3% of TMPTMA are optimum amounts of additives needed for long-chain branching process. The optimum blend could be a great alternative for foaming applications.

Structure-property correlation of an impact- modified random polypropylene copolymer

The combination of rheological and interfacial properties is utilized in this work to explain the thermal and mechanical properties of a random polypropylene copolymer (RPP) toughened with an ethylene-propylene copolymer (EPR). RPP/EPR blends are directly prepared by injection molding. The EPR exhibits higher viscosity in comparison with the RPP over the evaluated shear rate, while the RPP/EPR blends show similar viscosities at high shear rates. The interfacial properties indicate a strong interaction between the RPP and EPR domains. Differential scanning calorimetry analyses indicate that the EPR does not act as a nucleating agent for the RPP, with the RPP crystallinity only decreasing at high EPR contents, suggesting that the EPR can modify the RPP crystallite size. Scanning electron micrographs of the blends demonstrate a ductile fracture surface, indicating that EPR can increase the RPP tenacity. The RPP impact strength is improved by up to 102% in the RPP/EPR 90/10 wt.% blend, while the RPP deformation at break is increased from 183% to 246% after the incorporation of 10% EPR. The tensile strengths of the RPP and RPP/EPR blends are very similar, indicating that the RPP achieves a good balance between stiffness and toughness after being blended with the EPR.

Development of Polypropylene-Based Single-Polymer Composites With Blends of Amorphous Poly-Alpha-Olefin and Random Polypropylene Copolymer

We developed polypropylene-based single-polymer composites (PP-SPC) with blends of amorphous poly-alpha-olefin (APAO) and random polypropylene copolymer (rPP) as matrix material and polypropylene (PP) woven fabric as reinforcement. Our goal was to utilize the lower melting temperature of APAO/rPP blends to increase the consolidation of the composites and decrease the heat load of the PP reinforcement. We produced the composites by film-stacking at 160 °C, and characterized the composites with density, peel, static tensile and dynamic falling weight impact tests, and by scanning electron microscopy. The results indicate that consolidation can be enhanced by increasing the APAO content of the matrix. We found that the APAO content of 50% is optimal for tensile properties. With increasing APAO content, the perforation energy decreased, but even the well-consolidated composites showed very high perforation energy. In the case of a pure APAO matrix, fiber content can be increased up to 80 wt% without a severe loss of consolidation, resulting in good tensile properties. The PP-SPCs developed possessed excellent mechanical properties, and well-consolidated composites can be produced with APAO/rPP blends as a matrix with high fiber content.

Dynamically vulcanized elastoplastics based on the technologically compatible random polypropylene and butadiene-nitrile rubber

The basic physicomechanical properties of dynamically vulcanized elastoplastics based on random polypropylene and nitrile butadiene rubber are considered. It is shown that the higher the concentration of nitrile groups in the nitrile-butadiene rubber, the higher the limiting concentration of the elastomer to appear rubber-like properties in elastoplastics. In order to improve the compatibility of the components of the mixture, a graft copolymer of polypropylene with methacrylic acid was used as a compatibilizer. In contrast to sulfuric vulcanization, peroxide one contributes to a signifi cant deterioration of the melt fl ow index of elastoplastics.

Development of Polypropylene-based Thermoplastic Elastomers with Crumb Rubber by Dynamic Vulcanization: A Potential Route for Rubber Recycling

In our current paper the preparation and properties of thermoplastic elastomer produced by dynamic vulcanization is presented and discussed. We dynamically vulcanized natural and styrene butadiene rubber (NR/SBR) phase by continuous extrusion. Dispersion and in-situ vulcanization of the rubber phase occurred simultaneously in a co-rotating twin screw extruder. We used a random polypropylene copolymer (rPP) as the thermoplastic matrix and untreated crumb rubber (CR) to partially substitute the neat fresh rubber in order to check whether this is a potential recycling route for waste rubber products. We studied the effect of various rubber formulations, various processing conditions (screw speed and configuration) and various CR particle size distributions by characterizing the mechanical performance of the thermoplastic dynamic vulcanizates (TDVs) with tensile and hardness tests and their morphology by evaluating SEM micrographs taken from the fracture surfaces of the tensile specimens. The results showed that increasing screw speed and more high-shear elements in the screw setup led to a finer dispersion of the rubber phase, resulting in improved mechanical properties. The ultimate tensile properties of the best TDVs reached 20.5 MPa in tensile strength and 550 % in strain at break. However, partial replacement of the fresh rubber with untreated CR caused a significant deterioration in mechanical properties, due to poor adhesion between the CR particles and the matrix and rubber. This suggests that some kind of pre-treatment (e.g. by microwave or other devulcanization techniques) is necessary to enhance the surface activity of the CR particles.

Chlorine Dioxide Degradation Issues on Metal and Plastic Water Pipes Tested in Parallel in a Semi-Closed System.

Chlorine dioxide (ClO2) has been widely used as a disinfectant in drinking water in the past but its effects on water pipes have not been investigated deeply, mainly due to the difficult experimental set-up required to simulate real-life water pipe conditions. In the present paper, four different kinds of water pipes, two based on plastics, namely random polypropylene (PPR) and polyethylene of raised temperature (PERT/aluminum multilayer), and two made of metals, i.e., copper and galvanized steel, were put in a semi-closed system where ClO2 was dosed continuously. The semi-closed system allowed for the simulation of real ClO2 concentrations in common water distribution systems and to simulate the presence of pipes made with different materials from the source of water to the tap. Results show that ClO2 has a deep effect on all the materials tested (plastics and metals) and that severe damage occurs due to its strong oxidizing power in terms of surface chemical modification of metals and progressive cracking of plastics. These phenomena could in turn become an issue for the health and safety of drinking water due to progressive leakage of degraded products in the water.

The influence of matrix crystallinity on the mechanical performance of short-fibre composites – Based on homo-polypropylene and a random polypropylene copolymer reinforced with man-made cellulose and glass fibres

This research shows the influence of the crystallinity of thermoplastic polymer matrix on the mechanical properties of short-fibre composites. It proves that crystal phase affects not only the properties of matrix but predominantly the transfer of stresses to fibres. The injection moulded composites were based on homo-polypropylene and random polypropylene copolymer matrices with glass and man-made cellulose short fibre reinforcements. They were also subjected to annealing to induce growth of crystal phase in the matrices, which was investigated using XRD, DSC and density measurements. The mechanical performance of applied polypropylenes and their composites was compared with annealed counterparts. This comparison shows that matrix crystallinity is important for the mechanical performance of composite and may cause its inconstancy induced by factors like variation of molecular mass distribution, processing conditions and cold crystallisation happening over time. This effect should be heeded at the production, exploitation and research on composites with semicrystalline matrices.

저점도 호모 폴리프로필렌 첨가가 랜덤 폴리프로필렌 필름 가공 특성과 구조 형성에 미치는 영향

용융캐스팅 폴리프로필렌 필름의 가공성 향상을 위하여 호모 폴리프로필렌이 사용되었다. 저점도 호모 폴리프로필렌을 첨가함에 따라 랜덤 폴리프로필렌의 점도가 감소하고 activation energy가 증가함에 따라 필름 가공성이 향상됨을 알 수 있었다. 고결정성 호모 폴리프로필렌 첨가에 의하여 필름의 열적 특성과 결정화도가 증가되었고 고상화 과정에서 상대적으로 작은 크기의 결정 생성에 의하여 표면 거칠기는 낮아짐을 확인하였다. 이러한 형태학적 변화는 필름 배향 및 결정화에 영향을 주며 그 결과, 연신 필름에서 결정화도와 기계적 특성이 크게 향상됨을 확인할 수 있었다.

Effect of wood flour addition and modification of its surface on the properties of rotationally molded polypropylene composites

The aim of this study was to assess the effect of wood flour addition and the treatment of its surface on the properties and structure of rotationally molded (rotomolded) polypropylene. In this study, a random polypropylene copolymer (rPP) micropellet was rotationally molded with the direct addition of 5 wt % of commercial grade of wood flour Lignocel C120, untreated (WF) and chemically treated (mWF). Part of the natural filler was chemically modified by a silanization process using 3-aminopropyltriethoxysilane (3-APS). The structure, quality and mechanical properties of the polypropylene and composite rotomolded parts were discussed in terms of changes in the material’s thermal properties, evaluated by differential scanning calorimetry (DSC), thermomechanical properties, obtained by dynamic mechanical-thermal analysis (DMTA), and dynamic rheological properties, assessed by oscillatory rheometry. The structure of composites and fillers was analyzed by means of a scanning electron microscopy (SEM), while the analysis of the chemical structure of materials and final products was carried out by a Fourier transform infrared spectrometry (FT-IR). It was found that adding the natural filler, despite the application of a preliminary drying and chemical treatment caused creation of the pores and decreased the overall mechanical properties of the composites. The lower processing ability of the composites was ascribed to a higher complex viscosity and an increase in the elastic behavior of molten composite materials in comparison to pure rPP.