Melt Flow Index Test Research Articles

Processability investigation on underlying mechanism of LLDPE-based rotationally moulded banana fibre biocomposites

Rotational moulding is a plastic manufacturing technique primarily used to create hollow items without stress. In the current work, the banana fibre in powder form is combined with linear low-density polyethylene (LLDPE) at concentrations ranging from 5% to 40% by weight. Several tests, including Fourier transform infrared spectroscopy (FTIR), melt flow index (MFI), water absorption, and differential scanning calorimetry, were carried out for three samples for each percentage and the average of those samples has been considered to support the requirements of processability for rotational moulding. The significance of LLDPE and banana fibre peaks can be seen in the 5–30 wt. % range, according to FTIR. The MFI test followed by FTIR results conferred a flow-ability ranging between 3.022 and 3.5 g/10 min for 5 to 15 wt.% which is considered to be appropriate. A water absorption test was conducted from 5 to 15 wt.% for the blend, it is observed as fibre content increases water absorption increases. Based on the analysis 15 wt. % sample has been discarded noting a high absorption rate of 7 wt. %. From the thermal analysis, the crystallisation temperature of 5% and 10% LLDPE/banana blend was found to be 110.20°C and 111.08°C, making it suitable for rotomouldability. From the testing results, it can be inferred that a banana fibre concentration of 10 wt. % or less in LLDPE is the optimal range for producing a blend with better processability for rotational moulding.

Mechanical properties of rCB-pigment masterbatch in rLDPE: The effect of processing aids and water absorption test

Abstract Homogenization of pigment is the key to coloring a plastic product evenly. In this article, the tensile properties of recovered carbon black merge with low molecular weight lubricants and other compounding ingredients in the form of pigment masterbatch (PM) added in a recycled low-density polyethylene (rLDPE) resin were evaluated. The prepared masterbatch with the varying amount and types of processing aids (A and B) was first compounded using the heated two-roll mill. Subsequently, the manually mixed masterbatch in rLDPE was put through an injection molding machine for the shaping process to produce an rLDPE pigment masterbatch composite (PMC). The tensile test was performed on the samples to evaluate the mechanical properties of the PMC. Meanwhile, the melt flow index test was executed to justify the composite flow characteristics. Fourier-transform infrared spectroscopy analysis and scanning electron microscopy were also carried out to analyze the PM and PMC chemical properties and their constructed surface morphology. Besides, X-ray diffraction analysis was performed to determine the changes in degree of crystallinity before and after the water absorption test. The addition of PM in rLDPE has slightly increased the rLDPE matrix tensile properties. While, the usage of more processing aid B in the PMC has turned out to secure better tensile properties compared to the addition of higher amount of processing aid A in the PMC. Interestingly, the tensile properties of all composites after the water absorption test were enhanced, suggesting that a stronger bond was formed during the immersion period.

Effect of the melt flow index of compatibilizer on the melt processing and properties of highly filled magnesium hydroxide/linear low density polyethylene composites

AbstractThe application of highly filled composites is limited by their poor processing and rheological properties due to the high loading of fillers. One possible solution to this problem is to use maleic anhydride grafted polypropylene (MAPP) with high melt index as compatibilizer and lubricant. Herein, magnesium hydroxide (MH)/linear low‐density polyethylene (LLDPE) composites with 60 wt% of MH were prepared using MAPP with three different melt flow indexes (MFI). The equilibrium torque and melt flow index tests show that the addition of MAPP with high MFI significantly improves the processability and flowability of MH/MAPP/LLDPE composites. The rheological studies show that it also leads to a substantial reduction in the viscosity and therefore MH/MAPP/LLDPE composites exhibit more solid‐like responses. The scanning electron microscopy shows that a transition layer is formed at the MH‐LLDPE interface. The flame retardancy test shows that the addition of MAPP slightly reduces the flame retardancy of the composites as evidenced by the reduced limiting oxygen index and increased total heat release. Cone calorimeter test shows that the simultaneous addition of MH and MAPP has a synergistic smoke suppression effect.

Effect of Functionalized Polyethylene Wax on the Melt Processing and Properties of Highly Filled Magnesium Hydroxide/Linear Low-Density Polyethylene Composites.

The poor processing and rheological properties of highly filled composites caused by the high loading of fillers can be improved with the use of maleic anhydride grafted polyethylene wax (PEWM) as compatibilizer and lubricant. In this study, two PEWMs with different molecular weights were synthesized by melt grafting, and their compositions and grafting degrees were characterized by Fourier transform infrared (FTIR) spectroscopy and acid-base titration. Subsequently, magnesium hydroxide (MH)/linear low-density polyethylene (LLDPE) composites with 60 wt% of MH were prepared using polyethylene wax (PEW) and PEWM, respectively. The equilibrium torque and melt flow index tests indicate that the processability and fluidity of MH/MAPP/LLDPE composites are significantly improved with the addition of PEWM. The addition of PEWM with a lower molecular weight leads to a substantial reduction in viscosity. The mechanical properties are also increased. The limiting oxygen index (LOI) test and cone calorimeter test (CCT) show that both PEW and PEWM have adverse effects on flame retardancy. This study provides a strategy to simultaneously improve the processability and mechanical properties of highly filled composites.

Assessment of the effect on the plasticizer diffusion of inorganic fillers in plasticized poly(vinyl chloride) composite films for cable sheath applications

AbstractIn cable sheath applications, plasticizer migration is important as it causes reduction in mechanical properties, deterioration, and pollution in transported environments. This study focuses on the effect of inorganic fillers on the diffusion of plasticizers from plasticized‐PVC cable films. Plastisols were prepared by mixing plasticizer, thermal stabilizers, and inorganic fillers (boric acid, boron clay, sintered calcined boron waste clay, talc, and zircon oxide) into the PVC resin. Plastigel films were cured and thermally aged at 100, 130, and 160°C. Oxidation index were determined by Fourier transform infrared spectroscopy. The diffusion coefficient and activation energies were calculated from mass loss. Thermogravimetric analysis analyses were performed to obtain weight loss. Fillers were characterized for their zeta potential, particle size distribution, polydispersion. Morphology of the fillers was also conducted using scanning electron microscopy. Their mechanical and rheological analyses were evaluated with the tensile and melt flow index test. The order of diffusivity was determined as the films having boric acid > undoped > talc = sintered boron clay > zircon > boron clay. The result of this evaluations is the addition of inorganic filler increases the mechanical and thermal applicability and reduces the plasticizer diffusion. It is thought that the results, will contribute to the studies on the plasticizer transition in cable applications.

Impact of Prepolymerization Monomer on Polymerization and Properties of LLDPE

One of the methods of synthesis of linear low-density polyethylene is the use of pre-polymerization method. In this research, propylene, 1-butene and ethylene were used as prepolymers at 35 ℃. Also, various tests were performed to analyze the obtained polymers by pre-polymerization method. The results obtained in the melt flow index test showed that ethylene monomer had the lowest value. It also had the better properties.

Processing and Mechanical Properties of Highly Filled PP/GTR Compounds.

Ground rubber from automobile tires is very difficult to recycle due to the cross-linking of the macromolecules and thus the lack of thermoplastic properties. The research consisted of assessing the processing possibility via the injection of highly filled PP/GTR compounds modified with 1.5 wt.% 2.5-dimethyl-2.5-di-(tert-butylperoxy)-hexane. GTR dosing ranged from 30 wt.% up to 90 wt.%. The evaluation of the processing properties of the obtained materials was carried out on the basis of the melt flow index test results and the signals recorded during processing by the injection molding by temperature and pressure sensors placed in the mold. The influence of the applied modifier on the changes in the mechanical properties of PP/GTR was determined with hardness, impact and static tensile tests. Moreover, thermal properties were obtained by the differential scanning calorimetry method. It has been found that it is possible to efficiently process compounds with high GTR content using injection molding. The presence of the filler allows to significantly reduce the cooling time in the injection mold and thus the time of the production cycle. It has been confirmed that 2.5-dimethyl-2.5-di-(tert-butylperoxy)-hexane modifies the rheological properties of PP and thus the PP/GTR composition. The lower viscosity of the matrix results in a more accurate bonding with the developed surface of the GTR grains, which results in better mechanical properties of the rubber-filled polypropylene.

Evaluation of flammability, thermal stability and mechanical behavior of expandable graphite-reinforced acrylonitrile–butadiene–styrene terpolymer

Acrylonitrile-butadiene-styrene (ABS) terpolymer was loaded with expandable graphite (EG) at four different concentrations of 5%, 10%, 15% and 20% using micro-compounder followed by injection molding process. Mechanical, thermomechanical, thermal, flame retardancy, melt flow and morphological characterizations of composites were done by tensile, hardness and impact tests, dynamic mechanical analysis (DMA), thermogravimetric analysis (TGA), melt flow index (MFI) test and scanning electron microscopy (SEM), respectively. According to test results, tensile strength and storage modulus of ABS were improved with the increase in EG content. Storage modulus and glass transition temperature of ABS yielded enhancement with the inclusion of EG. However, percent elongation and impact strength values showed decreasing trend with EG additions. ABS/EG composites gave higher fire performance relative to ABS including enhancement in LOI and reduction in heat release rate. MFI test revealed that incorporation of EG with the lowest amount displayed no dramatic change for MFI value of neat ABS. EG flakes exhibited well-dispersion and exfoliated structure for all of the filling ratios as the SEM microimages of composites were examined. 15% and 20% EG containing ABS composites were remarked as the most suitable candidates among prepared composites.

Characterization and processability of post-consumer, double-recycled high impact polystyrene from disposable cups

The aim of this work is to characterize high impact polystyrene (HIPS) from disposable cups of different shapes and colors, these post-costumer cups, obtained from informal collectors were first crushed using a shredder, giving small particles of about 5 mm in characteristic size. A small portion of these granules was dedicated to the MFI (Melt Flow Index), DSC (Differential scanning calorimetry), FTIR (Fourier Transformation infrared spectroscopy) and TGA (Thermo-gravimetric analysis) test, while the rest was molded using a SINTESI injection press. Cylinder and nozzle temperatures were set at 200° C and 180° C, respectively, while the mold was held at 45° C. The dimensions of the molded samples were for tensile and bending samples. In order to simulate the recycling process as accurately as possible, the disposable cups underwent 2 successive grinding/injection cycles, and during each cycle the tensile, flexural strength, DSC, IRFT, TGA and MFI tests were performed to evaluate the evolution of the thermos-mechanical properties of the material. The present analysis proved the possibility of reintegrating the double-recycled material into the plastic industry, as its properties were only slightly affected: especially in the case of thin-walled packaging.

Green thermoplastic poly(ether-urethane)s - synthesis, chemical structure and selected properties investigation

This work aimed to characterize the effect of the monomers chemical structure on the selected properties of the green thermoplastic poly(ether-urethane)s. During synthesis two types of polyether biopolyols, 4,4′-diphenylmethane diisocyanate and bio-based 1,3-propanediol were employed. Materials were synthesized with the use of two step method and two different prepolymers, which were mixed together in equimolar quantities. Obtained materials were characterized by spectroscopic method, size exclusion chromatography, thermal, static mechanical and melt flow index tests. It was confirmed that the prepolymers mixture has an effect on the thermal stability and selected properties of synthesized green thermoplastic poly(ether-urethane)s.

Mechanical, thermal, melt-flow and morphological characterizations of bentonite-filled ABS copolymer

PurposeThis study aims to investigate the mechanical, thermal, melt-flow and morphological behavior of acrylonitrile-butadiene-styrene (ABS)-based composites after bentonite inclusions. Melt mixing is the most preferred production method in industrial scale and basically it has very near processing parameters compared to 3D printing applications. Rheological parameters of ABS and its composites are important for 3D applications. Melt flow behavior of ABS effects the fabrication of 3D printed product at desired levels. Shear thinning and non-Newtonian viscosity characteristics of ABS make viscosity control easier and more flexible for several processing techniques including injection molding, compression molding and 3D printing.Design/methodology/approachABS copolymer was reinforced with bentonite mineral (BNT) at four different loading ratios of 5%, 10%, 15% and 20%. ABS/BNT composites were fabricated by lab-scale micro-compounder followed by injection molding process. Mechanical, thermo-mechanical, thermal, melt-flow and morphological properties of composites were investigated by tensile, hardness and impact tests, dynamic mechanical analysis (DMA), thermo-gravimetric analysis (TGA), melt flow index (MFI) test and scanning electron microscopy (SEM), respectively.FindingsMechanical tests revealed that tensile strength, elongation and hardness of ABS were enhanced as BNT content increased. Glass transition temperature and storage modulus of ABS exhibited increasing trend with the additions of BNT. However, impact strength values dropped down with BNT inclusion. According to MFI test measurements, BNT incorporation displayed no significant change for MFI value of ABS. Homogeneous dispersion of BNT particles into ABS phase was deduced from SEM micrographs of composites. Loading ratio of 15% BNT was remarked as the most suitable candidate among fabricated ABS-based composites according to findings.Research limitations/implicationsThe advanced mechanical properties and easy processing characteristics are the reasons for usage of ABS as an engineering plastic. Owing to the increase in its usage for 3D printing technology, the ABS became popular in recent years. The utilization of ABS in this technology is in filament form with various colors and dimensions. This is because of its proper rheological features.Practical implicationsMelt-mixing technique was used as preparation of composites, as this processing method is widely applied in industry. This method is also providing similar processing methodology with 3D printing technology.Originality/valueAccording to the literature survey, to the best of the authors’ knowledge, this study is the first research work regarding the melt-flow performance of ABS-based composites to evaluate their 3D printing applications and processability. ABS and BNT containing composites were characterized by tensile, impact and shore hardness tests, DMA, TGA), MFI test and SEM techniques.

Lignin/poly(butylene succinate) composites with antioxidant and antibacterial properties for potential biomedical applications

Lignin (LIG) is a renewable biopolymer with well-known antimicrobial and antioxidant properties. In the present work LIG was combined with poly(butylene succinate) (PBS), a biocompatible/biodegradable polymer, to obtain composites with antimicrobial and antioxidant properties. Hot melt extrusion was used to prepare composites containing up to 15% (w/w) of LIG. Water contact angle measurements suggested that the incorporation of LIG did not alter the wettability of the material. The material density increased slightly when LIG was incorporated (<1%). Moreover, the melt flow index test showed an increase in the fluidity of the material (from 6.9 to 27.7 g/10 min) by increasing the LIG content. The Young's modulus and the tensile deformation of the material were practically unaffected when LIG was added. Infrared spectroscopy and differential scanning calorimeter confirmed that there were interactions between LIG and PBS. The DPPH assay was used to evaluate the antioxidant properties of the materials. The results suggested that all the materials were capable of reducing the DPPH concentrations up to 80% in <5 h. Finally, LIG-containing composites showed resistance to adherence of the common nosocomial pathogen, Staphylococcus aureus. All tested materials showed ca. 90% less bacterial adherence than PBS.

Mechanical, thermo-mechanical and morphological characterization of ABS based composites loaded with perlite mineral

Acrylonitrile-butadiene-styrene (ABS) copolymer was filled with perlite mineral (PER) at four different loading level of 2.5%, 5%, 10% and 15%. ABS/PER composites were produced using lab-scale micro-compounder followed by injection molding process. Mechanical, thermo-mechanical, melt-flow and morphological properties of composites were reported by tensile and impact tests, dynamic mechanical analysis (DMA), melt flow index (MFI) test and scanning electron microscopy (SEM), respectively. Mechanical characterizations revealed that tensile strength, elongation and Youngs’ modulus of ABS were improved by PER inclusions. However, impact strength of ABS reduced with increase of PER concentration. Glass transition temperature of ABS displayed increasing trend for %5 concentration of PER. MFI test implied that PER addition caused slight decreasing for MFI value of unfilled ABS. Homogeneous dispersion of PER particles into ABS matrix for their lower loading level was obtained from SEM micrographs of composites. According to findings, 5% PER containing sample exhibited the best performance and it was remarked as the most suitable candidate among fabricated ABS based composites.

Thermomechanical investigations of PEKK-HAp-CS composites.

In this experimental study, a composite of poly-ether-ketone-ketone by reinforcement of hydroxyapatite and chitosan has been prepared for possible applications as orthopaedic scaffolds. Initially, different weight percentages of hydroxyapatite and chitosan were reinforced in the poly-ether-ketone-ketone matrix and tested for melt flow index in order to check the flowability of different compositions/proportions. Suitable compositions revealed by the melt flow index test were then taken forward for the extrusion of filament required for fused deposition modelling. For thermomechanical investigations, Taguchi-based design of experiments has been used with input variables in the extrusion process as follows: temperature, load applied and different composition/proportions. The specimens in the form of feedstock filament produced by the extrusion process were made to undergo tensile testing. The specimens were also inspected by differential scanning calorimetry and photomicrographs. Finally, the specimen showing the best performance from the thermomechanical viewpoint has been selected to extrude the filament for the fused deposition modelling process.

Preparation of Polystyrene-Starch Composite by Melt Extrusion and Evaluation of its Mechanical, Thermal Biodegradation Properties

In this work, composites of general-purpose polystyrene and corn starch with glycerol as a plasticizer were prepared in different ratios of starch and glycerol by melt mixing in the twinscrew extruder. The structure of prepared composites was studied using scanning electron microscopy analysis. Also, to evaluate the impact strength and thermal properties of composites, we used Izod impact strength test, melt flow index and Vicat softening temperature tests. Besides, to examine the interaction between composite elements, thermal stability, and degradation process, the samples were subjected to analysis using thermogravimetric analysis. Finally, to study the biodegradation properties, composite samples were buried in soil for 12 weeks and their weight changes were measured during two week periods. Biodegradation results and scanning electron microscopy analysis showed that the rate of biodegradation not only starch present in composites but also depends on the quality of starch particle dispersion. Notched Izod test showed the independence of samples impact strength to starch present. Due to the reduction of stress accumulation points, homogeneous dispersion of starch in the matrix leads to increase impact strength in unnotched Izod test. Melt flow index test showed that addition of starch and glycerol leads to respectively increase and decrease in composites’ viscosity.

Reactive processing preparation of sustainable composites from canola meal reinforced by chemical modification

Canola meal (CM), a by-product of canola oil extraction, was modified by poly (styrene-co-glycidyl methacrylate) (PSG) and could potentially be used as a sustainable natural composite. Infrared analysis indicated that PSG could efficiently react with the proteins in CM and become covalently bonded. DSC results revealed that the modified CM composites showed new glass transition temperatures (Tg) decreasing with the introduction of PSG, which were attributed to the disruption of intermolecular association. Torque curves and melt flow index tests showed the flow property of the modified CM composites increased due to interference by PSG of the hydrogen and disulfide bonding among the protein species. DMA results showed greater amorphous character for the modified CM composites and new glassy plateaus with increased storage moduli, indicating a change in molecular structure and enhancement in mechanical property and usability below Tg. Furthermore, the thermostability, the tensile strength, and the elastic moduli of the modified CM composites increased because of the formation of cross-linked proteins in the CM composites, which will potentially increase the application value in some fields, such as single-use agricultural planting containers replacing high-impact polystyrene (HIPS) containers, and food or coffee trays.

Evaluation of polypropylene hybrid composites containing glass fiber and basalt powder

Abstract Polypropylene composites filled with inorganic fillers are widely used due to their good mechanical and thermal properties. The modification efficiency of filler incorporated into thermoplastic polymer strongly depends on its shape and dimension. Therefore, the development of novel hybrid composites modified with particle and fibrous shaped fillers expands the range of thermoplastic composite applications. This work investigates the influence of glass fiber and basalt powder and their shape on the mechanical properties of polypropylene-based composites. Mechanical properties of hybrid composites were evaluated using static tensile test, impact resistance, and hardness measurements. The thermomechanical stability of the materials was evaluated via dynamic mechanical thermal analysis. Results indicated that the incorporation of inorganic fillers significantly improved the composite sample stiffness at a wide range of temperatures. The research was complemented with structure investigations realized using scanning electron microscopy. Moreover, the incorporation of basalt powder, which is well known for its low friction coefficient, improved the processing properties, as proven by the melt flow index test.

Detailed comparison of compatibilizers MAPE and SEBS-g-MA on the mechanical/thermal properties, and morphology in ternary blend of recycled PET/HDPE/MAPE and recycled PET/HDPE/SEBS-g-MA

In this study, for recycling polyethylene terephthalate, a blend of recycled polyethylene terephthalate (RPET) and high-density polyethylene (HDPE) with maleic anhydride polyethylene (MAPE) and maleic anhydride-grafted styrene–ethylene/butylene–styrene (SEBS-g-MA) were used. The effect of compatibilizers in RPET was investigated by mechanical test (tensile and flexural tests), thermal test (differential scanning calorimetry (DSC)), and melt flow index test. The morphology of fracture surface of samples was investigated by scanning electron microscopy (SEM). The mechanical tests showed that elongation at break point and the fracture energy of samples with composition of RPET (70 wt%)/HDPE (15 wt%)/MAPE (15 wt%) and RPET (75 wt%)/HDPE (10 wt%)/SEBS-g-MA (15 wt%) increased significantly. Results of DSC test and SEM photography showed that ternary blend of RPET/HDPE/MAPE has better compatibility compared with RPET/HDPE/SEBS-g-MA. SEM images showed that MAPE provides better bonding between RPET and HDPE compared with SEBS-g-MA. MAPE was dispersed in RPET better than SEBS-g-MA.

Mechanical, electrical, and melt flow properties of polyurethane elastomer/surface-modified carbon nanotube composites

Carbon nanotube-reinforced polyurethane elastomer composites were prepared by melt-mixing. Nitric acid oxidation and silanization were applied to carbon nanotube surfaces to achieve better interfacial interactions with polyurethane elastomer. Tensile and hardness tests, differential scanning calorimetry, melt flow index test, dielectric measurements, and morphological studies of composites were reported. The best results were obtained for surface-modified carbon nanotubes containing composites with lower loading levels. Addition of carbon nanotubes leads to almost two-fold increase in strain and modulus compared to pristine polyurethane elastomer. Tensile strength of composites was also improved by inclusion of carbon nanotubes. However, strength values drop down with increasing carbon nanotube content. Shore hardness increased with the inclusion of modified carbon nanotube to polyurethane elastomer while pristine carbon nanotube caused remarkable decrease in hardness of polyurethane elastomer. Relatively higher melting points and slightly lower glass transition temperatures were observed for carbon nanotube-loaded composites compared to polyurethane elastomer because of plasticizing effect of carbon nanotube. Incorparation of carbon nanotube to polyurethane elastomer matrix caused reduction in melt flow index values due to formation of agglomarates, and n the contrary, surface modifications of carbon nanotube exhibited increase in melt flow index thanks to enhanced interfacial interactions between carbon nanotube and polyurethane elastomer. Significant increase in dielectric constant of composites was observed. Better dispersion of surface modified carbon nanotubes into polyurethane elastomer was also concluded from SEM micrographs of composites.

Thermal, rheological and mechanical properties of poly(propylene carbonate)/methyl methacrylate–butadiene–styrene blends

Different amounts of core–shell methyl methacrylate–butadiene–styrene (MBS) impact modifiers were incorporated into biodegradable poly(propylene carbonate) (PPC) in a batch mixer, aiming at improving the mechanical properties and raising the glass transition temperature (T g) of PPC. A series of properties, such as thermal behavior, miscibility, rheological and mechanical properties, and the morphological analysis of PPC/MBS blends were investigated in detail. PPC was partially miscible with MBS according to the results of dynamic mechanical analysis tests which showed a little shift in the peaks associated with the glass transition temperatures. The differential scanning calorimetry results showed that the T g of PPC increased gradually as MBS content increased. Additionally, the thermal stability properties of the blends were improved dramatically. The rheological properties obtained by the melt flow index tests indicated that the melting viscosities of PPC/MBS blends increased with the addition of MBS, and all melting viscosities of the polymer blends were higher than those of pure PPC. The mechanical properties of PPC/MBS blends implied that the elongation at break increased from 5.3 % of pure PPC to 52 % after incorporation of 20 % MBS into the blends. Accordingly, the impact test results indicated that MBS could toughen the PPC matrix effectively, about 3.7 times higher compared to pure PPC. The scanning electron microscopy studies on PPC/MBS blends showed that MBS particles were dispersed well in the PPC matrix when MBS content was below 10 %, whereas the aggregation could be clearly seen when the content of MBS was over 15 %.