scholarly journals Development of elasto-plastic eco-nano-materials for the footwear industry

2020 ◽  
Author(s):  
Maria Daniela Stelescu ◽  
Daniela Ioana Constantin ◽  
Maria Sonmez ◽  
Laurentia Alexandrescu ◽  
Mihaela Nituica ◽  
...  
Keyword(s):  
High Performance ◽  
Accelerated Aging ◽  
Polymeric Materials ◽  
Melt Flow Index ◽  
Flow Index ◽  
New Materials ◽  
Dynamic Vulcanization ◽  
Footwear Industry ◽  
Plastic Materials ◽  
Plasticized Starch

The paper refers to the obtaining of new types of eco-nano elasto-plastic materials with high-performance characteristics based on ethylene-propylene-terpolymer rubber (EPDM), high-density polyethylene (HDPE), plasticized starch and organically modified montmorillonite (OMMT). The new materials were obtained by the technique of dynamic vulcanization and melt intercalation in a Plasti-Corder Brabender internal mixer, at 80 rpm and a temperature of 170°C. The influence of using the OMMT type nanofiller and the plasticized starch filler on the characteristics was observed. The new materials have a melt flow index of over 12g/10 min at 180°C for a force of 10 kg, which allows injection processing - an ecological method of processing polymeric materials. The samples show very good physical-mechanical characteristics both in the normal state and after accelerated aging at 168 hours at 170°C (tensile strength over 16 N/ mm2, tear strength over 102 N/mm, hardness 55-59°ShD, elasticity over 30%, etc.). The materials show high values of abrasion resistance (below 30 mm3), and very good results for mass and volume variation after 22 hours at 23°C in: water, acids and concentrated bases. These characteristics are due both to the composition of the new materials and to the obtaining technology. For evaluating the structural modification, analysis of the FT-IR spectral of the samples was carried out. The new materials can be used in different fields such as: in the footwear industry (soles, heels and plates), safety equipment (boots, etc), obtaining gaskets, hoses, technical rubber products for cars etc.

scholarly journals Thermal degradation of polyethylene film materials due to successive recycling

2006 ◽  
Vol 220 (8) ◽  
pp. 1099-1108 ◽  
Author(s):  
R Marsh ◽  
A J Griffiths ◽  
K P Williams ◽  
S L Evans
Keyword(s):  
Physical Properties ◽  
Polymeric Materials ◽  
Melt Flow Index ◽  
Reliable Data ◽  
Flow Index ◽  
Plastic Film ◽  
Mechanical Recycling ◽  
Plastic Materials ◽  
The Uk ◽  
Processing Properties

Mechanical recycling of plastic film involves subjecting plastic materials to a series of heat cycles that can potentially degrade the material, causing brittleness and increased melt viscosity. Plastic film recycling in the UK is in its infancy, in need of an increased understanding of how the physical properties of polymeric materials change before and during the process. Reliable data are required to estimate the behaviour of such film products when recycled. Measurements were made as to the changes in physical properties of four different varieties of polyethylene (PE) film products when subjected to a series of successive simulated heat cycles and evaluated after each step. Results showed that although changes in tensile properties were fairly small, changes in processing properties such as melt-flow index for highly branched or low-density PE are substantial and could be a concern during recycling operations.

scholarly journals Effect of Hard Plastic Waste on the Quality of Recycled Polypropylene Blends

Recycling ◽  
2021 ◽  
Vol 6 (3) ◽  
pp. 58
Author(s):  
Patrizio Tratzi ◽  
Chiara Giuliani ◽  
Marco Torre ◽  
Laura Tomassetti ◽  
Roberto Petrucci ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Polymeric Materials ◽  
Melt Flow Index ◽  
Plastic Waste ◽  
Flow Index ◽  
Yield Strain ◽  
Melt Index ◽  
Polypropylene Blends ◽  
Post Industrial ◽  
Plastic Containers

The recycling of plastic waste is undergoing fast growth due to environmental, health and economic issues, and several blends of post-consumer and post-industrial polymeric materials have been characterized in recent years. However, most of these researches have focused on plastic containers and packaging, neglecting hard plastic waste. This study provides the first experimental characterization of different blends of hard plastic waste and virgin polypropylene in terms of melt index, differential scan calorimetry (DSC), thermogravimetric analysis (TGA), mechanical properties (tensile, impact and Shore hardness) and Vicat softening test. Compared to blends based on packaging plastic waste, significant differences were observed in terms of melt flow index (about 10 points higher for hard plastic waste). Mechanical properties, in particular yield strain, were instead quite similar (between 5 and 9%), despite a higher standard deviation being observed, up to 10%, probably due to incomplete homogenization. Results demonstrate that these worse performances could be mainly attributed to the presence of different additives, as well as to the presence of impurities or traces of other polymers, other than incomplete homogenization. On the other hand, acceptable results were obtained for selected blends; the optimal blending ratio was identified as 78% post-consumer waste and 22% post-industrial waste, meeting the requirement for injection molding and thermoforming.

PREDICTING THE FLOW PROPERTIES OF POLYAMIDE NANOCOMPOSITES BY USING VINOGRADOV-MALKIN MODEL

2015 ◽  
Vol 9 (3) ◽  
pp. 2446-2452
Author(s):  
Tomasz Mariusz Majka ◽  
Marcin Majka ◽  
Muhammad Kamrul Hasan
Keyword(s):  
Shear Rate ◽  
Flow Direction ◽  
Polymeric Materials ◽  
Melt Flow Index ◽  
Polyamide 6 ◽  
Flow Index ◽  
Melt Flow ◽  
Melt Flow Rate ◽  
Shear Rates ◽  
Different Temperatures

This article reports the prediction of the theoretical flow curves of polyamide composites by using Vinogradov-Malkin model. Determination of the melt flow index of polymeric materials is the first step to study viscosity-shear rate relationship. The viscosity of the composites at different temperatures were calculated by using the Williams, Landel'a and Ferry (WLF) equation. Other important rheological characteristics were calculated by using appropriate equations. One point method is employed to correlate the changes in viscosity with temperatures. As expected, it is found that incorporation of nanoclay to polyamide 6 (PA6) significantly decreases the Melt Flow Rate of the composites and hence, increases density. Addition of stabilizer further increases density of the PA6/nanoclay composites. The simulations of viscosity curves for PA6 composites were carried out at measurement temperature, 240°C and in the range of 180°C - 350°C with shear rate of 10-1 – 103 1/s. It is found that addition of nanoclay and stabilizer to PA6 decreases viscosity of the composites in the order of PA6/OMMT > PA6 > PA6/I1098 > PA6/OMMT/I1098 > PA6/MMT/I1098 > PA6/MMT. At higher shear rates, viscosity decreases in the same sequence as low shear rates. At further higher shear rates (> 1000 1/s), filler particles are arranged in the flow direction thus exerting no significant effect on viscosity of composites both with and without the stabilizer. During injection moulding in the shear rate ranging from 101 – 104 1/s at 240°C temperature, it is evident that viscosity decreases drastically with increase in shear rate.

Polymeric Alternatives in Manufacturing Removable Partial Dentures

2017 ◽  
Vol 54 (4) ◽  
pp. 754-756
Author(s):  
Lavinia Cosmina Ardelean ◽  
Cristina Maria Bortun ◽  
Angela Codruta Podariu ◽  
Laura Cristina Rusu
Keyword(s):  
High Performance ◽  
Polymeric Materials ◽  
New Materials ◽  
Alternative Technologies ◽  
High Performance Polymers ◽  
Lower Weight ◽  
Light Curing

Traditionally, removable partial dentures consist of a metallic framework, covered by acrylic saddles, which support acrylic or ceramic teeth. Because their shortcomings, new classes of resins/macromolecular compounds which promise better quality are nowadays available for manufacturing removable partial dentures: urethane-based resins, polyamides, acetal resins, high-performance polymers. Manufacturing these new materials implies alternative technologies like: injection, milling, light-curing. Using these alternative polymeric materials results in dentures with better resistance, elasticity, appearance and lower weight, which provide much more comfort to the patient.

An Experimental Investigation on Surface Quality Extruded Wood-Polypropylene Composite

2012 ◽  
Vol 428 ◽  
pp. 89-93 ◽  
Author(s):  
Ehsan Soury ◽  
Amir Hossein Behravesh ◽  
Nathan Jafarian Jam ◽  
Ali Haghtalab
Keyword(s):  
Surface Quality ◽  
Polymeric Materials ◽  
Melt Flow Index ◽  
Extrusion Process ◽  
Diameter Ratio ◽  
Flow Index ◽  
Screw Speed ◽  
Melt Temperature ◽  
Wood Content ◽  
Length To Diameter Ratio

This paper presents an experimental study on surface quality (roughness) for extruded wood plastic composites (WPC) in an extrusion process. A problem that usually occurs in production of extruded parts of polymeric materials, and in special case of WPC, is flow instabilities at the extrusion die exit. The instabilities lead to production of profiles with unacceptable surface quality. In this paper, the influences of the important material and process parameters on the surface quality are investigated. The variable parameters were selected as wood content, polymer melt flow index (MFI), screw speed, melt temperature, die diameter and finally length-to-diameter ratio of the die land. The experiments specified that increasing die land length-to-diameter ratio (L/D), die temperature and wood content and decreasing screw speed and polymer MFI lead to improve the surface quality.

Rotomolding and polyethylene composites with rotomolded lignocellulosic materials: A review

2020 ◽  
Vol 39 (11-12) ◽  
pp. 459-472
Author(s):  
Lumirca Del Valle Espinoza León ◽  
Viviane Alves Escocio ◽  
Leila Lea Yuan Visconte ◽  
Julio Cesar Jandorno Junior ◽  
Elen Beatriz Acordi Vasques Pacheco
Keyword(s):  
Maleic Anhydride ◽  
Polymer Matrix ◽  
Polymer Melt ◽  
Polymeric Materials ◽  
Melt Flow Index ◽  
Polymer Particle ◽  
Morphological Properties ◽  
Flow Index ◽  
Main Process ◽  
Wood Fibers

Rotomolding is a versatile process used in the manufacture of thermoplastic polymeric materials to produce large hollow plastic parts. The aim of this review article was to discuss the rotomolding process and show the properties of the polyethylene composite and rotomolded lignocellulosic fibers, which are processed for prolonged periods under temperature. The main process parameters studied are the shaft speed of the equipment, molding temperature, polymer particle size, polymer melt flow index, and amount of material, which must be well controlled to achieve a non-degraded product with homogeneous thickness and no porosity. Rotomolded composites containing sisal, pine, coir, banana, flax, and maple wood fibers, among others, have been evaluated primarily for their mechanical (impact, flexural, and tensile strength) and morphological properties. The type, content, and treatment of lignocellulosic fillers are the most widely studied variables in polyethylene-based rotomolded composites. Fiber content was the variable that most influenced mechanical properties, particularly impact strength and hardness due to the voids formed by the hydrodynamic volume between the polymer matrix and lignocellulosic filler. Chemical treatment of the fiber by mercerization with NaOH made it more hydrophobic and the addition of maleic anhydride-grafted polyethylene as a coupling agent improved the interfacial adhesion between the non-polar polymer matrix and polar filler. However, the best mechanical property results were obtained with the use of maleic anhydride-grafted polyethylene.

scholarly journals The Influence of the Accelerated Aging Conditions on the Properties of Polyolefin Geogrids Used for Landfill Slope Reinforcement

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1874
Author(s):  
Agnieszka Kiersnowska ◽  
Wojciech Fabianowski ◽  
Eugeniusz Koda
Keyword(s):  
Mechanical Properties ◽  
Relative Elongation ◽  
Oxidative Degradation ◽  
Accelerated Aging ◽  
Melt Flow Index ◽  
Flow Index ◽  
Scanning Calorimetry ◽  
Oxidation Induction Time ◽  
Aging Test ◽  
Different Temperatures

Polyolefin geosynthetics are susceptible to oxidative degradation, which in turn leads to diminished mechanical properties in geotechnical constructions. When using these materials, it is extremely important to determine their durability over time in particularly aggressive conditions. In order to prolong the life of a geosynthetic material, antioxidants are added during the manufacturing process. The function of antioxidants is to prevent polymer oxidation reaction in time. As the antioxidant content is depleted, the polymer becomes less protected towards oxidative attacks. This article describes the aging process of uniaxial (high density polyethylene) HDPE geogrids under the influence of chemical and environmental factors. Evaluations of accelerated aging test of the uniaxial HDPE geogrids were incubated in simulated landfill conditions for a period of 12 months. Three temperatures (25 °C, 45 °C, and 75 °C) were selected for carrying out the aging experiments in aqueous solutions mimicking landfill conditions. The changes observed by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR) and melt flow index (MFI) correlate with the mechanical properties of the aged geogrid. No significant changes in the FTIR and MFI were observed over the 12 months of accelerated aging tests at none of the three different temperatures. The oxidation induction time (OIT) test showed no antioxidant remaining in the geogrid following eight months of aging test at 75 °C. No significant changes in the influence of accelerated aging tests on the average relative elongation at 25 °C and 45 °C of the tested material were observed. Accelerated aging tests at 75 °C showed that the mean elongation of 12.12% for the sample not subjected to accelerated aging tests (new sample) increased to 19.32% (after 12 months of incubation).

The Effect of Polyquinone and Phenol-Phosphite Stabilizer on the Resistance of Polypropylene to Ionizing Radiation

2019 ◽  
Vol 816 ◽  
pp. 328-332 ◽  
Author(s):  
M.S. Lisanevich ◽  
Elvina R. Rakhmatullina ◽  
Yu.N. Khakimullin ◽  
Rezeda Yu. Galimzyanova ◽  
R.M. Akhmadullin ◽  
...  
Keyword(s):  
Ionizing Radiation ◽  
Medical Devices ◽  
Polymeric Materials ◽  
Melt Flow Index ◽  
Flow Index ◽  
Radiation Sterilization ◽  
Melt Flow ◽  
Medical Products ◽  
Degradation Temperature

For polymeric materials intended for the manufacture of disposable sterile medical devices, resistance to sterilization methods is important. For the manufacture of disposable medical products is widely used polypropylene, destructive during radiation sterilization. It is established that the addition of polyquinone leads to a decrease in the destruction of polypropylene, which is manifested in a decrease in the values of the melt flow index and an increase in the degradation temperature of polypropylene of the irradiated compositions.

scholarly journals New Evidences on the Process Sensitivity of Some Renewable Blends Based on Starch considering Their Melt Rheological Properties

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Doina Dimonie ◽  
Marius Petrache ◽  
Celina Damian ◽  
Liliana Anton ◽  
Miruna Musat ◽  
...  
Keyword(s):  
Rheological Properties ◽  
Corn Starch ◽  
Polymeric Materials ◽  
Melt Flow Index ◽  
Melt Processing ◽  
Chemical Degradation ◽  
Flow Index ◽  
Cross Linking ◽  
Temperature Sensitive ◽  
Renewable Materials

The degradability and processability of new renewable materials based on starch and PVOH were studied using the melt flow index (MFI) method by measuring the melt rheological properties which depend not only on the extrusion conditions and material formulation but also on the macromolecule characteristics which can be modified by chemical degradation. These results were correlated with other material properties like color and cross-linking degree. The obtained results show that flowing in the melted state of the studied materials is accompanied by a second process of chains chemical degradation. It was observed that, at the same level of additivation, under identical extrusion conditions, the melted blends with corn starch as main component are highly mechanically sensitive and degrade mostly by chains scission and those with PVOH as major component are highly temperature sensitive and degrade mainly by cross-linking. The obtained results show also that each PVOH-starch blend requires particular formulation and individual windows of melt processing conditions. These results are a good proof that the MFI method is a good path to study the degradability and moldability of process sensitive polymeric materials like those based on starch and PVOH.

scholarly journals Pigmentation and Degradative Activity of TiO2 on Polyethylene Films Using Masterbatches Fabricated Using Variable-Frequency Ultrasound-Assisted Melt-Extrusion

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3855
Author(s):  
Christian J. Cabello-Alvarado ◽  
Zoe V. Quiñones-Jurado ◽  
Víctor J. Cruz-Delgado ◽  
Carlos A. Avila-Orta
Keyword(s):  
Mechanical Stability ◽  
Contrast Ratio ◽  
Accelerated Aging ◽  
Melt Flow Index ◽  
Flow Index ◽  
Melt Flow ◽  
Melt Extrusion ◽  
Yellowness Index ◽  
Tio2 Particles ◽  
Ultrasound Assisted

Ultrasound-assisted melt-extrusion method (USME) is a high-quality process used to produce polymeric compounds with an adequate homogeneous dispersion. This study evaluates white-color films of linear low-density polyethylene (LLDPE) prepared using TiO2 masterbatch obtained by ultrasound-assisted melt-extrusion at variable frequencies (USME-VF). LLDPE with three different melt-flow indices (2, 20 and 50 g/10 min) were used as the polymer matrix. The films were obtained from the dilution of masterbatches of LLDPE (melt-flow index = 2) at a concentration of 7 wt% TiO2. The morphology, pigmentation, TiO2 reactivity, and the mechanical stability of the films were assessed. The masterbatch compounds were evaluated by melt-flow index (MFI) and scanning electron microscopy (SEM). The contrast ratio, yellowness index and mechanical properties of films were also measured. The properties of whiteness and elongation at break improved in the films prepared using masterbatches with higher dispersion. Though the reactivity of the TiO2 particles increased during accelerated aging, it did not affect the elongation to rupture. The yellowness index was moderately affected in films that included TiO2 particles processed using USME-VF.

Sign in / Sign up

Export Citation Format

Share Document