Polypropylene Content Research Articles

Recombination Kinetics of Radicals in Polymers: Magnetic Field Effects

The results of kinetic studies of the recombination of radicals in the cage and in bulk of polymers obtained by nanosecond laser photolysis are summarized. The films of rubbers (poly(ethylene-co-butylene)), biaxially oriented polypropylene depending on the preliminary heat treatment, polystyrene, craton (polystyrene-block-poly(ethylene-butylene)-block-polystyrene), silicones, and acrylates are studied. By direct observation, the significant effect of the magnetic field on the kinetics of the recombination of radicals both in the cage and in the bulk of rubber films is recorded. Stretching the rubber film significantly delays the escape of radicals from the matrix cage and, accordingly, bimolecular recombination in the bulk (when stretched 3 times, both processes slow down by a factor of 2). The effect is significantly higher that that expected based on the change in the free volume of the polymer. The increased content of polypropylene in the rubber leads to a stronger cage effect due to the slower escape of radicals into the bulk; at the same time, the recombination rate in the bulk increases and the reaction takes place in the restricted areas of the polymer matrix. The comparative analysis of the kinetic characteristics in polymer of different classes is carried out.

The Behavior of Polymeric Blends (PP + PA6) in Tensile Tests

This paper presents the influence of component concentration for a class of polymeric blends with different concentration of PP (polypropylene) and PA6 (polyamide 6) and a constant concentration of additives: CaCO3, LDPE (low density polyethylene) and a compatibilizer POLYBOND� 3200. Mechanical properties has been investigated for four different test speeds, from 10 mm/min to 1000 mm/min. Young�s modulus performs in a band between 1500...1900 MPa, except for the value for PA6 at the lowest testing speed (v=10 mm/min), that is 1444 MPa. At high concentration of PA6, there were noticed voids in the longitudinal direction of the samples, forming large parallel �empty channels�, as the two polymers are immiscible. Except for values at low testing speed, the average values for tensile stress at break perform in a band of less than 8 MPa. The elongation at break is less than 10% for all materials, except for PA6 at the lowest testing speed, when a higher value was obtained. The lowest values were obtained for the blend with 20% PA6. For blends with 60% and 80% PA6, the difference between values, at the same testing speed, is the smallest. Energy at break has a slightly increase with the concentration of PA6. From the mechanical point of view, among the formulated blends, material D (with 80% PA6) is the most promising as has the highest values for stress and energy at break (11.8 J at v=10 mm/min and 9.6 J at v=1000 mm/min), but values are still less than those for PA6.

The effects of three different microplastics on enzyme activities and microbial communities in soil

Soils always receive microplastics (MPs) from plastic mulching, compost, and sewage irrigation, but the effects of MPs on soil environment remain largely unexplored. The objectives of this study were to investigate the effects of three MPs (membranous polyethylene (PE), fibrous polypropylene (PP), and microsphere PP) on enzyme activities and microbial community structure in one loamy and sandy soil. The concentration of microsphere PP (2mg/g) was one-tenth of those of the other two MPs (20mg/g). The results showed that the effects of three MPs on urease, dehydrogenase, and alkaline phosphatase activities followed the order: fibrous PP>membranous PE>microsphere PP, membranous PE>microsphere PP>fibrous PP and fibrous PP>microsphere PP>membranous PE, respectively. Results from high-throughput sequencing of 16S rRNA revealed that the membranous PE and fibrous PP raised the alpha diversities of the soil microbiota, whereas the diversity indexes of microbiota on MPs surfaces were significantly lower than those in the amended soils. MPs significantly altered the microbial community structure, especially for the enrichment of Acidobacteria and Bacteroidetes, the depletion of Deinococcus-Thermus and Chloroflexi. Aeromicrobium, Streptomyces, Mycobacterium, Janibacter, Nocardia, Arthrobacter were prone to inhabit on the MPs surfaces. PRACTITIONER POINTS: Three microplastics had different effects on soil enzyme activities. Fibrous PP had a more persistent effect on microbial activity. Membranous PE and fibrous PP raised the alpha diversities of soil microbiota. The effects of membranous PE and fibrous PP on microbial communities were similar. Distinct microbial communities were enriched on the surfaces of microplastics.

The product strength analysis of woven bag made from recycled mineral water plastic cups based on the polypropylene content

The increasing amount of plastic wastes has become a threat to the sustainability of all ecosystem in this Earth. This paper aims to provide an alternative utilization of plastic wastes as the raw material in the manufacturing process of woven bag products with a quality control in its tenacity. The initial phase of this research is a literature review on the concept of green manufacturing, woven bag quality, compositions of plastic wastes and woven bag manufacturing proses. Furthermore, it is followed by a data measurement in a form of tenacity test using a thread test gauge (tenacity). There are two types of the condition in the manufacturing process of woven bag production compared by increasing the temperature as much as 10°C in all the extraction machines. The measurement result shows that the average tensile strength in the production process of the woven bag made from the wastes of mineral water plastic cups with 10% composition and extraction temperature for the first condition is 3.38 g per 1 denier and the second condition is 4.76 g per 1 denier. The result of second condition manufacturing (increasing the extraction temperature by 10°C) after comparing it with the quality required by Standard National Indonesia (SNI) as much as 4 to 6 g per 1 denier is considered good quality. Therefore, through the concept of green manufacturing, the utilization of plastic wastes might provide a substitution to the part of plastic core raw material in the woven bag production. This research is designed to be the beginning of innovation to acquire raw materials for the woven bag, furthermore, the optimization toward the machine setting and innovation on plastic wastes raw materials become the foundation in increasing the tenacity.

Study of modified potassium feldspar as a novel β-nucleating agent to the crystal morphology and properties of polypropylene

In this paper, a modified potassium feldspar as high-efficiency polypropylene β-nucleating agent, which has the advantage of abundant resources and low price, was prepared by using bicyclo [2.2.1] hept-5-ene-2,3-dicarboxylic acid, We study the dosage of such nucleating agents affecting on β crystallization ability of isotactic polypropylene (iPP). Crystallization structure and morphology of the β nucleation of polypropylene are regulated and controlled by means of non isothermal crystallization, aiming that β crystal relative content (Kβ) of isotactic polypropylene reached 95.4%. Discussed the nucleation mechanism of the β-nucleating agent in the matrix and improved the toughness of iPP which is expected to realize the application of polypropylene in industry.

Identification and quantification of selected plastics in biosolids by pressurized liquid extraction combined with double-shot pyrolysis gas chromatography-mass spectrometry.

The identification and quantification of selected plastics (polystyrene (PS), polycarbonate (PC), poly-(methyl methacrylate) (PMMA), polypropylene (PP), polyethylene terephthalate (PET), polyethylene (PE) and polyvinyl chloride (PVC)) in biosolids (treated sewage sludge) was performed by pressurized liquid extraction (PLE) combined with double-shot pyrolysis gas chromatography-mass spectrometry. Validation of the method yielded recoveries of between 85 and 128% (mean RSD 11%) at a linear range of between 0.01 and 2μg. The distribution of plastics within 25 biosolid samples from a single wastewater treatment plant in Australia was assessed. The mass concentration of PE, PVC, PP, PS and PMMA was between 0.1 and 4.1mg/g dry weight (dw) across all samples, with a total plastic concentration ƩPlastics of between 2.8 and 6.6mg/g dw (median=4.1mg/g dw). PE was the predominant plastic detected (mean concentration of 2.2mg/g dw), contributing to 50% of the total of all plastics. Overall, this study demonstrates that pressurized liquid extraction (PLE) combined with double-shot pyrolysis gas chromatography-mass spectrometry can be used to identify and quantify PE, PP, PVC, PS, and PMMA in biosolids.

Strength characteristics of fiber-reinforced light shotcrete

The article presents the regularities of the flexural and compressive strength variation, as well as the energy intensity of destruction of light heat-shielding vermiculite concrete, depending on the content of polypropylene or basalt fiber. The paper stresses that the greatest increase in flexural strength of 40% is observed at the polypropylene or basalt fiber that the greatest increase in flexural strength of 40% is observed at the polypropylene or basalt fiber of 2 and 2-4% respectively. As the basalt fiber content increases from 1 to 4%, the compressive strength increases from 42 to 83%. The resistance of vermiculite concrete to dynamic bending loads when the polypropylene fiber ranges from 0.5 to 2% by a factor of 2.5 4.2. With basalt fiber content of 1 to 4% the energy intensity of destruction increases 1.5 2.5 times.Specific energy intensity of destruction of samples reinforced with basalt fiber increases by 2.3 ÷ 2.7 times during volumetric destruction of the specimens under study on a vertical pile driver. The regularities obtained in the course of the studies indicate that fiber reinforcement of light heat-shielding vermiculite concrete increase its strength characteristics and thereby expand the scope of its application.

Preparation of PBT/POE‐g‐GMA/PP ternary blends with good rigidity–toughness balance by core–shell particles

ABSTRACTCompared with poly(butylene terephthalate)/glycidyl methacrylate grafted poly(ethylene–octene) (PBT/POE‐g‐GMA) binary blends, supertough PBT‐based ternary blends with little rigidity loss were successfully obtained by adding rigid polypropylene (PP) into PBT/POE‐g‐GMA blends to construct core–shell particles during melt blending. The effects of PP content and type on the phase morphology and mechanical properties of the blends were systematically investigated. Theoretical predictions and scanning electron microscopy observation showed that a core–shell structure was formed in PBT matrix with PP as the core and POE‐g‐GMA as the shell. The mechanical property tests showed that POE‐g‐GMA and PP had significant synergistic toughening effect. When PP with high melt flow index (H‐PP) was used, PBT/POE‐g‐GMA/H‐PP (70/15/15) blends possessed the highest Izod notched impact strength, which was 1.9‐fold compared with PBT/POE‐g‐GMA (70/30) binary blends, while the tensile performance loss was little. The essential work of fracture tests was performed to evaluate the fracture resistance of different samples. The results demonstrated that PBT/POE‐g‐GMA/PP ternary blends possessed much better resistance to crack propagation than PBT/POE‐g‐GMA binary blends. The decrease of interparticle distance and the fibrillation of core–shell particles activated intense matrix shear yielding, which was the reason for the high crack resistance of ternary blends. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48872.

Influence of Spinning Temperature and Filler Content on the Properties of Melt-Spun Soy Flour/Polypropylene Fibers

Polypropylene (PP) fibers are heavily used in disposable nonwovens fabrics because of their desirable properties and low-cost, but they are not biodegradable. With the goal of reducing non-biodegradable plastic waste in the environment, the primary aim of this study was to produce fibers with reduced content of PP for disposable fabrics by incorporating soy flour, a bio-based renewable material. An optimum processing temperature of 190 °C was established, and thin fibers with a diameter under 60 µm were successfully melt-spun. Inclusion of compatibilized soy (SFM) at 30 wt% resulted in fibers with a tensile modulus of 674 ± 245 MPa and a yield strength of 18 ± 4 MPa. At 15 wt% SFM, fiber tensile modulus and yield strength were 914 ± 164 and 29 ± 3, respectively. Although lower than those of neat PP fibers (1224 ± 136 MPa and 37 ± 3 MPa), these SFM/PP fiber properties are suitable for nonwoven applications. Additionally, partial presence of soy particulates on fiber surface imparted enhanced water absorption and colorability properties to the fibers while imparting the fibers the feel of natural fibers.Although more difficult to produce, soy-PP fibers possessed similar properties as compared to those of than soy-PE fibers reported in earlier studies.

The effects of maleated polybutadiene‐grafted polypropylene (MAPB‐g‐PP) content on the properties of wood flour/polypropylene composites

This research investigated the effects of a compatibilizer of maleated polybutadiene‐grafted polypropylene (MAPB‐g‐PP) on the properties of wood‐flour/polypropylene composites through the analysis of mechanical properties, water absorption, thermogravimetry, differential scanning calorimetry, and scanning electronic microscopy. The results demonstrate that the mechanical properties of composites were significantly increased; the thermal stability and water absorption were improved. The crystallization temperature and crystallinity were decreased. These improvements have been attributed to the strong interfacial interaction of MAPB‐g‐PP with both wood and polypropylene. J. VINYL ADDIT. TECHNOL., 26:17–23, 2020. © 2019 Society of Plastics Engineers

Effect of microplastics exposure on the photosynthesis system of freshwater algae.

Microplastics are widely distributed in freshwater environments. At present, most of the studies on the toxicity of microplastics are concentrated on aquatic feeding animals, but relatively few have addressed freshwater algae. This study investigated the effect of microplastics (polypropylene (PP) and polyvinyl chloride (PVC)) exposure on the photosynthetic system of freshwater algae over the logarithmic growth period. The results showed that both PVC and PP had a negative effect on chlorophyll a concentrations of Chlorella (C.) pyrenoidosa and Microcystis (M.) flos-aquae; among them, when the concentration of PVC exceeded 250 mg/L, compared with the control group, the chlorophyll a content of C. pyrenoidosa was reduced by 55.23%. For photosynthetic activity, higher concentrations of PVC and PP can induce lower values of Fv/Fm, Fv/F0, and Fv'/Fm', suggesting a larger impact in algae. However, algae were able to adjust, with increased values of Fv/Fm, Fv/F0, and Fv'/Fm'. This dose-negative effect phenomenon also exists in the study of the rapid light-response curves. In addition, comparing the two microplastics, we could see that PVC greatly inhibits the photosynthesis system of freshwater algae. Our study confirmed that microplastics can affect algae growth under certain concentrations, which provides evidence for understanding the risks of microplastics.

Study on the in-situ synthesis and the crystallization, mechanical, dielectric properties of Polypropylene/Polybutene-1

Polymeric materials are widely used as capacitor diaphragm materials because of their good pressure resistance, low dielectric loss, good processing performance and good compatibility with devices. In this experiment, the Polypropylene/Polybutene-1 (PP/PB-1) resin was prepared by the reaction of butene-1 polymerization using the modified intermittent bulk polypropylene polymerization reactor. The structure and morphology of the prepared PP/PB-1were characterized by DSC, POM and FT-IR so on. The effects of different prepolymerization time on their crystalline morphology and mechanical properties were investigated. As the polypropylene prepolymerization time becomes longer, the content of Polypropylene in the synthesized polybutene-1 sample increased gradually, and the spherulitic size and nucleation time of polybutene-1 were changed. In addition, the tensile properties of the product were also improved. The PP/PB-1 film was prepared by the film drawing machine using synchronous biaxial stretching method. It was found that when the tensile temperature was 130°C and the tensile rate was 40mm / min, the prepared PP/PB-1 films had the best dielectric properties. At this time, the dielectric constant was 2.9, and the dielectric loss tangent was low (<0.005).

Effect of internal donors on the performance of Ti-Mg catalysts in propylene polymerization: Donor introduction during or after MgCl2 formation

Propylene polymerization catalysts with different internal donors (ID) are synthesized by two methods: (1) a standard method with ID introduction during formation of MgCl2 by reacting Mg(OEt)2 with TiCl4, and (2) the introduction of ID on MgCl2 already formed in the presence of butyl acetate (the substitution method). 1,3-diether, dibutyl phthalate (DBP) and pentane-2,4-diol-dibenzoate (PDDB) are used as ID. Catalysts prepared with the same ID by both methods slightly differ in their composition, activity and stereospecificity (the content of xylene soluble polypropylene (PP) fraction). But the catalyst active sites produce PP, whose properties (melt flow index, MFI, and molecular-weight distribution as Mw/Mn) depend on ID in the same manner for both methods of catalyst synthesis. Hence, the effect of ID on the catalyst active sites is not related with the effect of ID on the formation of MgCl2 crystallites with different cuts.

Effects of different polypropylene and ammonium lignosulfonate contents on the crystallization behavior, rheological behaviors, and mechanical properties of ethylene propylene diene monomer/ polypropylene/ ammonium lignosulfonate composites

Thermoplastic elastomer (TPE), made from ethylene propylene diene monomer (EPDM) and polypropylene (PP) based on reactive blending, has excellent processing performance and characteristics and a wide range of applications. However, there are currently no reports in the literature regarding the usage of TPE in making composite boards. In this paper, EPDM, PP, and ammonium lignosulfonate (AL) were used as the raw materials, polyethylene wax was used as the plasticizer, and a dicumyl peroxide vulcanization system with dynamic vulcanization was used to make a new kind of composite material. This research studied the influences of the PP and AL contents on the crystallization behavior, mechanical properties, and rheological properties of the composites. The results showed that the PP content had a noticeable impact on the performance of the composites. The AL content had a major impact on the modulus of elasticity of the composite board. Accordingly, this kind of composite material can be used as an elastomer material for the core layer of laminated flooring.

Mechanical and thermal properties of bamboo fiber reinforced polypropylene/polylactic acid composites for 3D printing

In this article, a kind of degradable composite was prepared from bamboo fiber (BF), poly lactic acid (PLA), and polypropylene (PP). The mechanical and thermal properties were characterized by the universal testing machine, thermogravimetric analysis, differential scanning calorimetry. In order to improve the compability between BF and polymer matrix several modification on the surface of BF were explored and compared. Moreover, a compatibilizer (maleated PP) was applied to further increase compatibility between the fiber and matrix. It is found that the thermal stability of BF/PP/PLA composites decreased with the increase of maleated polypropylene (MAPP) content. When 5% MAPP was used the tensile strength, flexural strength, and impact strength of composites reached 33.73, 47.18 MPa, and 3.15 KJ/m2, with an increase by 13, 11.7, and 23.5%, respectively, compared with the composites without MAPP. The improvement of mechanical properties is attributed to the fact that irregular grooves and cracks induced by the modification of BF facilitate the infiltration of polymer into fiber due to the strong capillary effect. Furthermore, BF/PP/PLA composites are potential to be used in 3D printing. POLYM. ENG. SCI., 59:E247–E260, 2019. © 2018 Society of Plastics Engineers

Thermal and curl properties of PET/PP blend fibres compatibilized with EAG ternary copolymer

Blends of polyethylene terephthalate (PET)/polypropylene (PP) and the ternary copolymer ethylene–acrylic ester–glycidyl methacrylate (EAG) as the compatibilizer were prepared using a twin-screw extruder. The thermal properties, densities and morphologies of the blends were determined using various techniques. Next, PET/PP blend fibres were prepared using a melt–spinning system, and their curl properties were investigated. Scanning electron microscopy (SEM) results showed that the number of PP particles in the PET matrix and size of the PP phase decreased as the EAG content increased. The melting temperature \((T_{\mathrm{m}})\) and cooling crystallization \((T_{\mathrm{cc}})\) values of PP in the PET/PP blends decreased significantly after the addition of 1% EAG. The density of the PET/PP blend fibres decreased significantly with increase in the EAG and PP contents. After curl formation, the curl length of PP in the fibres was shorter than that of PET.

Effects of maleated polypropylene content on the extended creep behavior of wood‒polypropylene composites using the stepped isothermal method and the stepped isostress method

This study investigated the effectiveness of maleated polypropylene (MAPP) as a coupling agent for improving the physico-mechanical properties and creep resistances of wood‒polypropylene composites (WPCs). The results revealed that the composites with MAPP showed significantly decreased water absorption and thickness swelling, while the flexural properties and the wood screw holding strength increased as the MAPP content increased up to 3 wt%. Additionally, flexural creep tests were conducted at a series of elevated temperatures and stresses using the stepped isothermal method (SIM) and the stepped isostress method (SSM), respectively. The SSM-predicted creep compliance curves fit better with the experimental data than the SIM-predicted curves. On the other hand, the creep master curves for all of the WPCs were constructed from different SSM test conditions and were highly consistent with the long-term experimental creep data. The creep resistance values of the composites with MAPP were greater than those without MAPP, especially for the WPC with 5 wt% MAPP (WPCM5), due to the improvement in the interfacial compatibility between the wood fibers and PP matrix. Furthermore, according to the SSM-predicted creep behavior, the improvement in creep resistance (ICR) of WPCM5 reached 61% over a 20-year period compared to the WPC without MAPP.

A novel combination of sandwich and co‐continuous structure based on polypropylene and styrene‐butadiene‐styrene block copolymer formed with wide range of polypropylene content

ABSTRACTThe styrene–butadiene–styrene block copolymer (SBS)/polypropylene (PP) blends with a unique sandwich layered co‐continuous structure were prepared by melt compounding. Differing from single conventional co‐continuous and sandwich structure, this structure was formed, where pure PP and co‐continuous SBS/PP phase acting as the face sheets and core. Even though the volume content was 20 or 10 vol %, PP always amazingly formed a continuous phase in SBS/PP blends, whereas the morphology of SBS phase relatively changed from dispersed particles to continuous network as its content increased to 50 vol %. For immiscible SBS/PP blends, due to the huge difference of complex viscosity and surface tension between SBS and PP, a pure PP layer existed on the surface of blends which can be ascribed to the PP enrichment. Herein, the structure of blends with more than 50 vol % SBS was presented as sandwich layered co‐continuous structure by combining the pure PP layer and co‐continuous structure. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46580.

Comparison of Mechanical Properties of Normal &amp; Polypropylene Fiber Reinforced Concrete

Concrete is the most commonly used construction material in the world. However, normal weight concrete shows less resistance to flexure. This research dealt with the technique to improve material efficiency in flexure as well as in compression, using polypropylene fibers. Different samples of concrete were prepared containing different dosages of polypropylene fibers (0.1%, 0.2%, 1% and 2% of the total concrete volume). The samples were then tested in compression and flexure, after 7, 14 and 28 days. The experimental investigation showed that the fibers increase the flexural strength of concrete in elastic range, when used in a specific limit. Maximum efficiency from the material was obtained at 0.2% dosage of fibers. Below and above this percentage the flexural and compressive strengths start decreasing. The experimental results also confirmed that with the gradual increase in polypropylene content the water absorption of concrete increases.

Evaluation and verification of the virgin–recycled mixing ratio of polypropylene plastic

This study has analyzed the properties of blended polypropylene (PP) specimens and employed statistical analysis to develop a method for determining the virgin–recycled mixing ratio of a specimen. Morphological observations and analyses of thermal and mechanical properties were conducted to examine specimen properties. The results were incorporated into regression analysis to create relationship equations. The results revealed that the melt temperature ranged between 167 and 169 °C, melt index (MI) ranged between 7.59 and 18.36 g/10 min, viscosity decreased when the amount of recycled PP and the rotation speed increased, the maximum decomposition temperature decreased with an increase in recycled PP content and increased with the heating rate, activation energy (Ea) ranged between 39.91 and 12.07 kcal/mol, Young’s modulus ranged between 1121.1 and 1910.2 MPa, and impact strength ranged between 37.94and 49.41 J/m (no significant trends). Scanning electron microscopy showed unbroken fibrils distributed on the fracture surface of Specimens 1–3. Additionally, the tensile strain of these specimens was comparatively high. The fracture surfaces of the specimens showed favorable compatibility after undergoing impact tests. The results of regression analysis indicated that the mixing ratio achieved significant correlations with Ea, MI, and Young’s modulus. Thus, regression and multiple regression analysis were performed to create relationship equations.