Effects of Different Processing Techniques on the Properties of PLA

2012 ◽  
Vol 550-553 ◽  
pp. 2932-2935
Author(s):  
Hong Juan Zheng ◽  
Yan Rong Wang ◽  
Zhi Wei Zhao ◽  
Lin Qi Zhang
Keyword(s):  
Mixing Time ◽  
Processing Temperature ◽  
Processing Conditions ◽  
Mixing Conditions ◽  
Processing Property ◽  
Obvious Effect ◽  
Good Thermal Stability ◽  
Mixing Speed ◽  
Internal Mixing ◽  
Processing Techniques

PLA has excellent processing property and good thermal stability, which are closely related to the processing technology, and the general processing temperature can be controlled in 170~230°C. Effects of different processing conditions (internal mixing temperature, internal mixing time and internal mixing speed) on the properties of PLA were discussed. The results show that the mechanical properties and other performance of PLA can be obviously enhanced by internal mixing. Internal mixing time and internal mixing speed have little effects on the performance of PLA, but the internal mixing temperature has obvious effect on the properties of PLA. PLA has the optimum properties when the internal mixing time is 5min, internal mixing speed is 20r/min and internal mixing temperature is 190°C. The spherocrystal size and spherocrystal rate of PLA are influenced strongly by the mixing conditions.

Processing and Characterization of Palm Fiber-Polypropylene Composites

2011 ◽  
Vol 471-472 ◽  
pp. 145-150
Author(s):  
Ramazan Kahraman ◽  
Sarfraz Abbasi ◽  
Basel Abu-Sharkh
Keyword(s):  
Mechanical Performance ◽  
Mixing Time ◽  
Processing Parameters ◽  
Processing Temperature ◽  
Palm Fiber ◽  
Polypropylene Composites ◽  
Mixing Speed ◽  
Single Screw Extruder ◽  
Injection Molded

Composites of palm fiber and polypropylene were compounded using a mixing device at various temperatures, mixing times, and mixing intensities. Two mixing options were utilized. Either the mixing device was mounted with a mixer or a single screw extruder. The composites were subsequently injection molded into standard tensile specimens for mechanical characterization. Tests were performed to determine the effects of processing parameters such as the mixing and molding temperatures, mixing speed, and mixing time on the mechanical performance of the palm-polypropylene composite. The optimum processing conditions for the mixer were determined to be: Mixing Speed = 50 rpm, Mixing Time = 8 min, and Processing Temperature = 200°C. Optimum extruder conditions, on the other hand, were determined as 40 rpm extruder screw speed and processing temperatures of Zone 1=195°C, Zone 2=200°C, Zone 3=205°C, and Nozzle 210°C. Use of the extruder resulted in higher composite strength with much shorter processing time. Further studies are also being conducted to include coupling agents in the processing to improve the interfacial adhesion between the palm fibers and the polypropylene matrix.

Effect of Mixing Condition on the Mechanical Properties of Magnesium Based Composites

2015 ◽  
Vol 1087 ◽  
pp. 434-438
Author(s):  
Wan Nur Azrina Wan Muhammad ◽  
Yoshiharu Mutoh
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Mixing Time ◽  
Mixing Conditions ◽  
Mixing Condition ◽  
Mixing Speed ◽  
Sic Particle

The effects of mixing conditions, i.e; mixing speed and mixing duration on the mechanical properties of the magnesium based composites were investigated. The hardness, tensile strength and microstructure of composites were studied. It was found that increase of the mixing speed and prolong the mixing time can improved the distribution of SiC particle and mechanical properties of magnesium based composites.

Polyethylene/Clay Nanocomposites Prepared in an Internal Mixer: Effect of Processing Variable on Mechanical Properties

2015 ◽  
Vol 1105 ◽  
pp. 46-50 ◽  
Author(s):  
Onny Ujianto ◽  
Margaret Jollands ◽  
Nhol Kao
Keyword(s):  
Mechanical Properties ◽  
Mixing Time ◽  
Diffusion Mechanism ◽  
Clay Nanocomposites ◽  
Processing Conditions ◽  
Mixing Conditions ◽  
Material Degradation ◽  
Processing Variable ◽  
Internal Mixer ◽  
And Diffusion

Polymer/clay nanocomposites have been explored extensively over the last two decades. Many studies report nanocomposite properties. However, studies on the effect of processing conditions are still limited. This study evaluates the effect of rotor type, rotor rotation (rpm) and mixing time on mechanical properties of polyethylene organoclay composites. Samples were fabricated using two different rotors; roller and Banbury, in an internal batch mixer at various mixing conditions. The analysis shows that the Banbury rotor improved mechanical properties more than the roller rotor. Shear and diffusion mechanism, as well as material degradation, were the controlling factors at different processing conditions.

scholarly journals Current understanding and applications of the cold sintering process

2019 ◽  
Vol 13 (4) ◽  
pp. 654-664 ◽  
Author(s):  
Tong Yu ◽  
Jiang Cheng ◽  
Lu Li ◽  
Benshuang Sun ◽  
Xujin Bao ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Sintering Temperature ◽  
Applied Pressure ◽  
Processing Technique ◽  
Rechargeable Batteries ◽  
Processing Conditions ◽  
Ceramic Processing ◽  
Sintering Process ◽  
Novel Processing ◽  
Processing Techniques

Abstract In traditional ceramic processing techniques, high sintering temperature is necessary to achieve fully dense microstructures. But it can cause various problems including warpage, overfiring, element evaporation, and polymorphic transformation. To overcome these drawbacks, a novel processing technique called “cold sintering process (CSP)” has been explored by Randall et al. CSP enables densification of ceramics at ultra-low temperature (⩽300°C) with the assistance of transient aqueous solution and applied pressure. In CSP, the processing conditions including aqueous solution, pressure, temperature, and sintering duration play critical roles in the densification and properties of ceramics, which will be reviewed. The review will also include the applications of CSP in solid-state rechargeable batteries. Finally, the perspectives about CSP is proposed.

Rheology Innovation in the Study of Mixing Conditions of Polymer Blends during Chemical Reaction

2005 ◽  
Vol 15 (5) ◽  
pp. 314-325 ◽  
Author(s):  
C. Lacoste ◽  
L. Choplin ◽  
P. Cassagnau ◽  
A. Michel
Keyword(s):  
Reaction Time ◽  
Polymer Blends ◽  
Rheological Properties ◽  
Chemical Reaction ◽  
Mixing Time ◽  
Reactive Systems ◽  
Diffusion Time ◽  
Mixing Conditions ◽  
Stirred Tanks ◽  
Polymer Blending

Abstract Polymer melts can be mixed with many monomers, plasticizers, antistatics or foaming additives. Properties of such mixtures can change during blending because of chemical reactions like polymerization or crosslinking. The process may be carried out either in stirred tanks, extruders or in motionless mixers. In this paper we focused on the mixing time and the diffusion time of reagent, plasticizer and polymer thanks to rheological tools, and on the way how rheological properties can be studied during chemical reaction in polymer blending. The concept of rheoreactor and Couette analogy were introduced since we have a reactor on our disposal that can mix solution and measure rheological properties without taking sample. This apparatus appears to be an appreciable tool in complement of internal mixers that are specific to polymer blending. For example, we show the importance of the competition between mixing time and reaction time for reactive systems.

Effect of High Shear Mixing Parameters and Degassing Temperature on the Morphology of Epoxy-Clay Nanocomposites

2013 ◽  
Vol 652-654 ◽  
pp. 159-166 ◽  
Author(s):  
Muneer Al-Qadhi ◽  
Nesar Merah ◽  
Khaled Mezghani ◽  
Zafarullah Khan ◽  
Zuhair Gasem ◽  
...  
Keyword(s):  
Mixing Time ◽  
Diglycidyl Ether ◽  
Clay Nanocomposites ◽  
High Shear ◽  
X Ray Diffraction ◽  
Transmission Microscopy ◽  
Clay Dispersion ◽  
Mixing Speed ◽  
Shear Mixing ◽  
Mixing Method

Epoxy-clay nanocomposites were prepared by high shear mixing method using Nanomer I.30E nanoclay as nano-reinforcement in diglycidyl ether of bisphenol A (DGEBA). The effect of mixing speed and time on the nature and degree of clay dispersion were investigated by varying the mixing speed in the range of 500-8000 RPM and mixing time in the range of 15-90 minutes. The effect of degassing temperature on the morphology of the resultant nanocomposites was also studied. Scanning and transmission microscopy (SEM & TEM) along with x-ray diffraction (XRD) have been used to characterize the effect of shear mixing speed, mixing time and degassing temperature on the structure of the resultant nanocomposites. The SEM, TEM and XRD examinations demonstrated that the degree of clay dispersion was improved with increasing the high shear mixing speed and mixing time. The results showed that the optimum high shear mixing speed and mixing time were 6000 rpm and 60 min, respectively. It was observed that the structure of the nanocomposites that have been degassed at 65oC was dominated by ordered intercalated morphology while disordered intercalated with some exfoliated morphology was found for the sample degassed at 100oC for the first 2 hours of the degassing process.

scholarly journals Potato Starch Hydrogels Produced by High Hydrostatic Pressure (HHP): A First Approach

Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1673 ◽  
Author(s):  
Dominique Larrea-Wachtendorff ◽  
Gipsy Tabilo-Munizaga ◽  
Giovanna Ferrari
Keyword(s):  
Mechanical Properties ◽  
Hydrostatic Pressure ◽  
High Hydrostatic Pressure ◽  
Potato Starch ◽  
Water Concentration ◽  
Medium Size ◽  
Processing Temperature ◽  
Processing Conditions ◽  
Scanning Calorimetry ◽  
Absorption Bands

Starch-based hydrogels have received considerable interest due to their safe nature, biodegradability and biocompatibility. The aim of this study was to verify the possibility of producing natural hydrogels based on potato starch by high hydrostatic pressure (HHP), identifying suitable processing conditions allowing to obtain stable hydrogels, as well as to characterize structural and mechanical properties of these products. Sieved (small size granules and medium size granules) and unsieved potato starch samples were used to prepare aqueous suspensions of different concentrations (10–30% w/w) which were processed at 600 MPa for 15 min at different temperatures (25, 40 and 50 °C). Products obtained were characterized by different techniques (light and polarized microscopy, Fourier transform infrared spectroscopy (FTIR), rheology and differential scanning calorimetry (DSC)). Results obtained so far demonstrated that potato starch suspensions (20% starch–water concentration (w/w)) with granules mean size smaller than 25 µm treated at 600 MPa for 15 min and 50 °C showed a complete gelatinization and gel-like appearance. Potato HHP hydrogels were characterized by high viscosity, shear-thinning behavior and a highly structured profile (G’ >> G’’). Moreover, their FTIR spectra, similarly to FTIR profiles of thermal gels, presented three absorption bands in the characteristic starch-gel region (950–1200 cm−1), whose intensity increased with decreasing the particle size and increasing the processing temperature. In conclusion, potato starch hydrogels produced by HHP in well-defined processing conditions exhibited excellent mechanical properties, which can be tailored according to the requirements of the different applications envisaged.

Effects of structure and processing on the surface roughness of extruded co-continuous poly(ethylene) oxide/ethylene-vinyl acetate blends

2020 ◽  
Vol 40 (9) ◽  
pp. 763-770 ◽  
Author(s):  
Molin Guo ◽  
Hao Chen ◽  
João M. Maia
Keyword(s):  
Surface Roughness ◽  
Ethylene Oxide ◽  
Vinyl Acetate ◽  
Stress Transfer ◽  
Ethylene Vinyl Acetate ◽  
Processing Temperature ◽  
Processing Conditions ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene ◽  
Different Molecular Weight

AbstractSurface roughness and sharkskin of extruded polymers, including blends are affected by the morphology and processing conditions. In this study, different effects on the roughness of the polymer blend extrudates were investigated. Co-continuous poly(ethylene) oxide/ethylene-vinyl acetate (PEO/EVA) blends with three different molecular weight (Mw) PEOs were compounded successfully. It was found that the better co-continuity of the structure and smoother surface were achieved for lower Mw PEO/EVA blend because of more effective stress transfer in the PEO phase. The effect of processing temperature was also studied with decreasing processing temperature reducing the surface roughness of the high Mw PEO/EVA blend, which was also achieved as a result of improved co-continuous morphology by adjusting the viscosity and elasticity ratio with shifting temperatures.

scholarly journals Effect of Low Mixing Speed on the Properties of Prolonged Mixed Concrete

2020 ◽  
Vol 6 (8) ◽  
pp. 1581-1592
Author(s):  
Ahmed Mohamed Abd El-Motaal ◽  
Ahmed Abdel-Reheem ◽  
Mohamed Mahdy
Keyword(s):  
Compressive Strength ◽  
Mixing Time ◽  
Mixing Process ◽  
Mixing Speed ◽  
Chemical Admixtures ◽  
Mixing Parameters ◽  
Slump Flow ◽  
Long Time ◽  
Ready Mixed Concrete ◽  
Mixed Concrete

The mixing process of concrete consists of dispersing the constituent ingredients (i.e. cement, admixtures, sand, and gravel) in water to homogeneous and solid product. The properties of the final product depend on mixing parameters such as mixing time and mixing speed. Ready Mixed Concrete (RMC) should be mixed for a long time with limited speed until delivered to the working site. This long time depends on long transport distances and traffic conditions. The present study investigated the effects of long mixing time on the properties of concrete without any change in its proportions during the mixing process and the effects of using the chemical admixtures: super plasticizers and retarders on its effectiveness, using a drum batch mixer. It has two directions of rotation: one for mixing concrete and the other for discharging it. This research identified concrete mixtures with local available materials i.e. cement, sand as fine aggregates, dolomite as coarse aggregates, water and chemical admixtures. Mixtures were prepared with the same cement and water content with constant sand to dolomite ratio with different dosages of chemical admixtures. Chemical admixtures were used to keep concrete flow during mixing. Mixtures were prepared with low mixing speed 1rpm for identified long mixing times more than 90 minutes from adding water to other components Slump and compressive tests were used as measurement tools of fresh and hardened concrete Retempering with extra water or chemical admixtures was prevented through mixing, so mixtures were extracted without target slump value. Findings showed that low mixing speeds made mixtures more effective for long times, the exceeding mixing time led to minimize water to cement ratio due to reduction of water content, and there was an inverse relationship between slump flow and compressive strength in case of no re-tempering. Therefore, slump flow of mixtures decreased by time, but on the other hand, compressive strength enhanced i.e. stiffening took place. The present study proved that the properties of the final product depends on mixing parameters such as mixing time and mixing speed, and that Ready Mixed Concrete (RMC) would be more effective if mixed for a long time with limited speed until transported to the work site. In addition, chemical admixtures with prolonged mixed concrete should be used to improve workability rather than compressive strength.

scholarly journals Microfibrillated Cellulose Grafted with Metacrylic Acid as a Modifier in Poly(3-hydroxybutyrate)

Polymers ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3970
Author(s):  
Marius Stelian Popa ◽  
Adriana Nicoleta Frone ◽  
Ionut Cristian Radu ◽  
Paul Octavian Stanescu ◽  
Roxana Truşcă ◽  
...  
Keyword(s):  
Active Sites ◽  
High Efficiency ◽  
Microfibrillated Cellulose ◽  
New Method ◽  
Processing Temperature ◽  
Lower Efficiency ◽  
Chemical Route ◽  
Good Thermal Stability ◽  
Uniform Dispersion ◽  
The Fourier Transform

This work proposes a new method for obtaining poly(3-hydroxybutyrate) (PHB)/microfibrillated cellulose (MC) composites with more balanced properties intended for the substitution of petroleum-based polymers in packaging and engineering applications. To achieve this, the MC surface was adjusted by a new chemical route to enhance its compatibility with the PHB matrix: (i) creating active sites on the surface of MC with γ-methacryloxypropyltrimethoxysilane (SIMA) or vinyltriethoxysilane (SIV), followed by (ii) the graft polymerization of methacrylic acid (MA). The high efficiency of the SIMA-MA treatment and the lower efficiency in the case of SIV-MA were proven by the changes observed in the Fourier transform infrared FTIR spectra of celluloses. All modified celluloses and the PHB composites containing them showed good thermal stability close to the processing temperature of PHB. SIMA-modified celluloses acted as nucleating agents in PHB, increasing its crystallinity and favoring the formation of smaller spherulites. A uniform dispersion of SIMA-modified celluloses in PHB as a result of the good compatibility between the two phases was observed by scanning electron microscopy and many agglomerations of fibers in the composite with unmodified MC. The dual role of SIMA-MA treatment, as both compatibilizer and plasticizer, was pointed out by mechanical and rheological measurements. This new method to modify MC and obtain PHB/MC composites with more balanced stiffness–toughness properties could be a solution to the high brittleness and poor processability of PHB-based materials.

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