scholarly journals Correlation between Processing Parameters and Degradation of Different Polylactide Grades during Twin-Screw Extrusion

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1333 ◽  
Author(s):  
Olga Mysiukiewicz ◽  
Mateusz Barczewski ◽  
Katarzyna Skórczewska ◽  
Danuta Matykiewicz
Keyword(s):  
Molecular Weight ◽  
Processing Parameters ◽  
High Mass ◽  
Flow Index ◽  
Processing Temperature ◽  
Color Analysis ◽  
Twin Screw Extrusion ◽  
Melt Mixing ◽  
Screw Extrusion ◽  
Twin Screw

This article presents the effect of twin-screw extrusion processing parameters, including temperature and rotational speed of screws, on the structure and properties of four grades of polylactide (PLA). To evaluate the critical processing parameters for PLA and the possibilities for oxidative and thermomechanical degradation, Fourier-transform infrared spectroscopy (FT-IR), oscillatory rheological analysis, and differential scanning calorimetry (DSC) measurements were used. The influence of degradation induced by processing temperature and high shearing conditions on the quality of the biodegradable polyesters with different melt flow indexes (MFIs)was investigated by color analysis within the CIELab scale. The presented results indicate that considering the high-temperature processing of PLA, the high mass flow index and low viscosity of the polymer reduce its time of residence in the plastifying unit and therefore limit discoloration and reduction of molecular weight due to the degradation process during melt mixing, whereas the initial molecular weight of the polymer is not an essential factor.

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).

scholarly journals Effects of Pitched Tips of Novel Kneading Disks on Melt Mixing in Twin-Screw Extrusion

2017 ◽  
Vol 44 (5) ◽  
pp. 281-288 ◽  
Author(s):  
Yasuya Nakayama ◽  
Nariyoshi Nishihira ◽  
Toshihisa Kajiwara ◽  
Hideki Tomiyama ◽  
Takahide Takeuchi ◽  
...  
Keyword(s):  
Twin Screw Extrusion ◽  
Melt Mixing ◽  
Screw Extrusion ◽  
Twin Screw

scholarly journals Effect of Lignin Plasticization on Physico-Mechanical Properties of Lignin/Poly(Lactic Acid) Composites

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2089 ◽  
Author(s):  
Chan-Woo Park ◽  
Won-Jae Youe ◽  
Seok-Ju Kim ◽  
Song-Yi Han ◽  
Ji-Soo Park ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Coupling Agent ◽  
Interfacial Adhesion ◽  
Melt Flow Index ◽  
Poly Lactic Acid ◽  
Flow Index ◽  
Twin Screw Extrusion ◽  
Screw Extrusion ◽  
Twin Screw ◽  
Polymeric Diphenylmethane Diisocyanate

Kraft lignin (KL) or plasticized KL (PKL)/poly(lactic acid) (PLA) composites, containing different lignin contents and with and without the coupling agent, were prepared in this study using twin-screw extrusion at 180 °C. Furthermore, ε-caprolactone and polymeric diphenylmethane diisocyanate (pMDI) were used as a plasticizer of KL and a coupling agent to improve interfacial adhesion, respectively. It was found that lignin plasticization improved lignin dispersibility in the PLA matrix and increased the melt flow index due to decrease in melt viscosity. The tensile strength of KL or PKL/PLA composites was found to decrease as the content of KL and PKL increased in the absence of pMDI, and increased due to pMDI addition. The existence of KL and PKL in the composites decreased the thermal degradation rate against the temperature and increased char residue. Furthermore, the diffusion coefficient of water in the composites was also found to decrease due to KL or PKL addition.

scholarly journals Influence of Lignin and Polymeric Diphenylmethane Diisocyante Addition on the Properties of Poly(butylene succinate)/Wood Flour Composite

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1161 ◽  
Author(s):  
Chan-Woo Park ◽  
Won-Jae Youe ◽  
Song-Yi Han ◽  
Ji-Soo Park ◽  
Eun-Ah Lee ◽  
...  
Keyword(s):  
Wood Flour ◽  
Crystallization Rate ◽  
Melt Flow Index ◽  
Kraft Lignin ◽  
Flow Index ◽  
Twin Screw Extrusion ◽  
Butylene Succinate ◽  
Screw Extrusion ◽  
Twin Screw ◽  
Higher Temperature

Poly(butylene succinate) (PBS)/wood flour (WF) composites with different WF content were prepared by twin-screw extrusion at 160 °C. With increasing WF content, the tensile strength of the PBS/WF composite without polymeric diphenylmethane diisocyante (pMDI) decreased, while that of the composite with pMDI increased. The addition of kraft lignin (KL) deteriorated the tensile properties of the composites both with and without pMDI. The melt flow index (MFI) decreased with increasing WF content, but increased with increasing KL content. The addition of pMDI caused an increase in the melt viscosity of the PBS/WF and PBS/WF/KL composites, resulting in a decrease in the MFI. The composites had lower thermal stability than neat PBS. The exotherms of the PBS/WF (50/50) composite appeared at a higher temperature than that of the neat PBS, but the PBS/WF/KL (50/50/20) composites had similar exotherms as the neat PBS. The addition of KL caused a decrease in the crystallization rate of PBS.

Development of nanocellulose-reinforced PLA nanocomposite by using maleated PLA (PLA-g-MA)

2017 ◽  
Vol 31 (8) ◽  
pp. 1090-1101 ◽  
Author(s):  
Somayeh Ghasemi ◽  
Rabi Behrooz ◽  
Ismail Ghasemi ◽  
Reza Shahbazian Yassar ◽  
Fei Long
Keyword(s):  
Cellulose Nanofibers ◽  
Fracture Morphology ◽  
Poly Lactic Acid ◽  
Twin Screw Extrusion ◽  
Melt Mixing ◽  
Force Microscopy ◽  
Heat Distortion Temperature ◽  
Uniform Dispersion ◽  
Screw Extrusion ◽  
Twin Screw

The goal of this research was improving the mechanical and physical properties of poly lactic acid (PLA) using cellulose nanofiber (CNF) as reinforcing and maleated PLA (PLA-g-MA) as a compatibilizer. PLA/nanocellulose composites were prepared through melt mixing with maleated PLA (5 wt%) and two levels of cellulose nanofibers (CNFs) (3 and 5 wt%) using twin screw extrusion. Nanocomposites fracture morphology, thermal properties, crystallization behavior, and mechanical behavior were determined as a function of cellulose nanofibers and PLA grafted on maleic anhydride content using scanning electron microscopy (SEM), atomic force microscopy, heat distortion temperature (HDT), impact, and tensile testing. The SEM micrographs confirmed the uniform dispersion of CNF within PLA matrix in the presence of maleated PLA. Among nanocellulose and compatibilizer, the latter one has better role in enhancement of nanocomposites HDT. Compatibilized nanocomposites (PLA/CNF5/PLAgMA5) exhibited maximum impact strength which was 131% higher than that of neat PLA. Compared to pure PLA, 138 and 40% improvements for the tensile strength and Young’s modulus can be obtained for the resulting nanocomposite with PLA/CNF5/PLAgMA5, respectively.

scholarly journals PLA/PA Bio-Blends: Induced Morphology by Extrusion

Polymers ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 10 ◽  
Author(s):  
Violeta García-Masabet ◽  
Orlando Santana Pérez ◽  
Jonathan Cailloux ◽  
Tobias Abt ◽  
Miguel Sánchez-Soto ◽  
...  
Keyword(s):  
Mechanical Performance ◽  
Reactive Extrusion ◽  
Processing Parameters ◽  
Poly Lactic Acid ◽  
Twin Screw Extrusion ◽  
Extrusion Die ◽  
Screw Extrusion ◽  
Twin Screw ◽  
Speed Rotation

The effect of processing conditions on the final morphology of Poly(Lactic Acid) (PLA) with bio-based Polyamide 10.10 (PA) 70/30 blends is analyzed in this paper. Two types of PLA were used: Commercial (neat PLA) and a rheologically modified PLA (PLAREx), with higher melt elasticity produced by reactive extrusion. To evaluate the ability of in situ micro-fibrillation (μf) of PA phase during blend compounding by twin-screw extrusion, two processing parameters were varied: (i) Screw speed rotation (rpm); and (ii) take-up velocity, to induce a hot stretching with different Draw Ratios (DR). The potential ability of PA-μf in both bio-blends was evaluated by the viscosity (p) and elasticity (k’) ratios determined from the rheological tests of pristine polymers. When PLAREx was used, the requirements for PA-μf was fulfilled in the shear rate range observed at the extrusion die. Scanning electron microscopy (SEM) observations revealed that, unlike neat PLA, PLAREx promoted PA-μf without hot stretching and the aspect ratio increased as DR increased. For neat PLA-based blends, PA-μf was promoted during the hot stretching stage. DMTA analysis revealed that the use of PLAREx PLAREx resulted in a better mechanical performance in the rubbery region (T > Tg PLA-phase) due to the PA-μf morphology obtained.

On mechanical, thermal and morphological investigations of almond skin powder-reinforced polylactic acid feedstock filament

2019 ◽  
pp. 089270571988601 ◽  
Author(s):  
Rupinder Singh ◽  
Ranvijay Kumar ◽  
Pawanpreet ◽  
Mohit Singh ◽  
Jatenderpal Singh
Keyword(s):  
Polylactic Acid ◽  
Mechanical Performance ◽  
Melt Flow Index ◽  
Extrusion Process ◽  
Melt Processing ◽  
Flow Index ◽  
Twin Screw Extrusion ◽  
Fused Filament Fabrication ◽  
Screw Extrusion ◽  
Twin Screw

The almond skin powder is one of the biodegradable and biocompatible food wastes that can be used as reinforcement in polylactic acid (PLA) for preparation of biomedical scaffolds/implants (for high mechanical performance) by fused filament fabrication. The present study deals with the melt processing of almond skin powder as reinforcement from 0 wt% to 5 wt% in the PLA matrix by twin-screw extrusion process. The results of the study suggested that reinforcing the almond skin powder as 2.5 wt% in the PLA matrix mechanically strengthens the feedstock filaments but the increase in the proportion up to 5 wt% reduces the mechanical strength to a significant level. A similar trend has been observed in differential scanning calorimeter observations for thermal stability analysis. As regard to the rheological property is concerned, the melt flow index shows a significant reduction with reinforcement of almond skin powder in PLA. The results are also supported by photomicrographic analysis (for surface properties) and Taguchi-based optimization of twin-screw extrusion process parameters (for multifactor optimization).

scholarly journals Effect of Carbon Fillers in Ultrahigh Molecular Weight Polyethylene Matrix Prepared by Twin-Screw Extrusion

2016 ◽  
Vol 07 (12) ◽  
pp. 863-880 ◽  
Author(s):  
Luiz Felipe M. Rocha ◽  
Suellem B. Cordeiro ◽  
Leonardo C. Ferreira ◽  
Flávio James H. Ramos ◽  
Maria de Fátima Marques
Keyword(s):  
Molecular Weight ◽  
Ultrahigh Molecular Weight Polyethylene ◽  
Twin Screw Extrusion ◽  
Polyethylene Matrix ◽  
Ultrahigh Molecular Weight ◽  
Screw Extrusion ◽  
Twin Screw ◽  
Carbon Fillers
Sign in / Sign up

Export Citation Format

Share Document