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 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.

Preparation of high molecular weight and elastic copolyester by reactive extrusion with diisocyanate compound for laser printing process

2012 ◽  
Vol 32 (3) ◽  
Author(s):  
Hyung-Jin Roh ◽  
Doe Kim ◽  
Dong-Ho Lee ◽  
Keun-Byoung Yoon
Keyword(s):  
Rheological Properties ◽  
Loss Modulus ◽  
Complex Viscosity ◽  
Melt Flow Index ◽  
Reactive Extrusion ◽  
Flow Index ◽  
Printing Process ◽  
Laser Printing ◽  
Printing Processes ◽  
Trimethylol Propane

Abstract A branched copolyester was synthesized using dimethyl terephthalate (DMT), 2,2-bis[4-(2-hydroxypropoxy)phenyl]propane, ethylene glycol (EG) and 2-(hydroxymethyl)-2- ethylpropane-1,3-diol (trimethylol propane, TMP). The branched copolyester and p-phenylene diisocyanate (PPDI) were melt extruded to enhance the melt viscosity and elasticity for use as a toner binder in the laser printing process. The effects of PPDI content on melt, thermal and rheological properties of the chain-extended copolyester were investigated. The melt flow index (MI) decreased with increasing amount of PPDI, due to a reaction between the hydroxyl chain end and isocyanate group. The storage modulus, loss modulus and complex viscosity of the chain extended copolyester were higher and the modified Cole-Cole plots revealed the chain extended copolyester to have higher elasticity than that of the branched copolyester. The chain extended copolyester exhibited suitable melt and rheological properties for applications as a toner binder in the laser printing processes.

scholarly journals Melt Rheology of Renewable Polymers and of New Materials Based on them as Tool in Controlling the 3D/4D Printability

2021 ◽  
Vol 57 (4) ◽  
pp. 77-87
Author(s):  
Doina Dimonie ◽  
Nicoleta Dragomir
Keyword(s):  
Molecular Weight ◽  
Melt Flow Index ◽  
Melt Processing ◽  
Operating Conditions ◽  
Flow Index ◽  
Flow Conditions ◽  
Index Method ◽  
Pre Treatment ◽  
Processing Techniques ◽  
Selection Of

The article presents results regarding the use of the melt flow index method (MFIM) in estimating the rheological properties of polylactic acid (PLA) and PLA-based materials, as tool in the selection of the operating conditions at their shaping into filaments and for 3D printing with thus obtained filaments. Based on the MFIM, the molecular weight of various PLA grade commonly used in melt processing techniques, including printing, were qualitatively compared. It was found that PLA for printing has the lowest molecular weight as compared with the PLA melt processed through injection, extrusion, thermoforming. It has been also shown that the MFIM can be used to verify the efficiency of drying, pre-treatment always needed to be done, before filaments obtaining and/or printing, especially in case of renewable polyesters. By simulating the printing at the indexer, via depositing successive layers, one over the other, it was possible to estimate the optimal flow conditions that ensure a good adhesion between the deposited layers. The estimation of the condition which ensure the needed adhesion between the deposited layers with the help of the MFIM was verified with good results on a grade of high loaded PLA achieved according to an original formulation.

Mixtures of Recycled Milk Pouches with a Virgin LDPE-LLDPE Blend

2005 ◽  
Vol 21 (3) ◽  
pp. 219-230 ◽  
Author(s):  
Arup Choudhury ◽  
Mandira Mukherjee ◽  
Basudam Adhikari
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Rheological Properties ◽  
Melt Flow Index ◽  
Flow Index ◽  
Thermal And Mechanical Properties ◽  
Melt Flow ◽  
Recycled Materials ◽  
Elongation At Break

The present investigation deals with the viability of the use of recycled milk pouch material, which is a 50:50 mixture of LDPE and LLDPE, and the scope for improvement of its properties by combining it with virgin LDPE-LLDPE (50/50). Melt flow index (MFI), rheological properties, thermal and mechanical properties of the pure materials and their formulated blends containing recycled milk pouches were studied. The properties of the recycled materials were not as satisfactory as those of the corresponding virgin materials. But a significant improvement in viscosity, crystallinity, tensile strength and elongation at break of the recycled LDPE-LLDPE material was achieved by blending it with the corresponding virgin LDPE-LLDPE blend.

On secondary recycling of ZrO2-reinforced HDPE filament prepared from domestic waste for possible 3-D printing of bearings

2019 ◽  
pp. 089270571986462 ◽  
Author(s):  
Rupinder Singh ◽  
Ranvijay Kumar ◽  
Shubham Tiwari ◽  
Shubham Vishwakarma ◽  
Shivam Kakkar ◽  
...  
Keyword(s):  
Acrylonitrile Butadiene Styrene ◽  
Melt Flow Index ◽  
Melt Processing ◽  
Thermoplastic Composites ◽  
Flow Index ◽  
Wear Properties ◽  
Twin Screw Extrusion ◽  
Screw Extrusion ◽  
Twin Screw ◽  
Recycled Hdpe

In this study, an innovative route for secondary recycling (with zirconium oxide (ZrO2) reinforcement) has been proposed based on melt processing of high-density polyethylene (HDPE) in low-temperature bearing applications. Initially, secondary recycled HDPE, acrylonitrile butadiene styrene, and nylon 6 thermoplastic composites were investigated for melt flow index (MFI) according to ASTM D1238 standard. Based on the acceptable MFI, secondary recycled HDPE matrix was selected for second-stage processing on twin screw extrusion (TSE). The final process involves reinforcement of ZrO2 into HDPE matrix by TSE in 60:40 ratio (by weight %) for preparation of feedstock filament (for possible 3-D printing of bearings). The results of the study suggest that for processing of HDPE, 40% ZrO2 composite matrix, 50 r min−1 screw speed, 190°C barrel temperature, and 15 kg applied load are the best setting of TSE (for maximizing the tensile strength of feedstock filament). The results are also supported by wear properties, thermal stability, and morphological analysis (based on scanning electron microscopy and electron-dispersive X-ray analysis).

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.

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.

Kinetic considerations on the mechanical behaviour of polypropylene + wood flour and polypropylene + sisal fibre blends

e-Polymers ◽  
2004 ◽  
Vol 4 (1) ◽  
Author(s):  
Carmen Albano ◽  
Rebeca Poleo ◽  
Jacobo Reyes ◽  
Miren Ichazo ◽  
Jeanette González ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Behaviour ◽  
Wood Flour ◽  
Melt Flow Index ◽  
Degradation Process ◽  
Chain Scission ◽  
Flow Index ◽  
Cross Linking ◽  
Γ Irradiation ◽  
Sisal Fibre

Abstract This work is aimed at analyzing by means of simple mathematical models the effect of different integral doses of γ-irradiation on the mechanical properties and concentration of radicals of the blends of polypropylene (PP) + wood flour and PP + sisal fibre. The analysis of the results permits inferring that the kinetic behaviour of the mechanical properties and the concentration of radicals at low integral doses (≤ 10 KGy) are indicative of a complex degradation process, implying the possibility of cross-linking and chain scission reactions both in the polymer as well as in the filler. Consequently, it can be concluded that cross-linking reactions are predominant. The behaviour observed at higher irradiation doses means that both reactions (cross-linking and chain scission) occur, the breaking reactions being the prevailing ones. This study of the kinetic analysis of the tensile properties is based on the behaviour detected for the melt-flow index.

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.

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.

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