Effects of carbon nanofibers on crystalline structures and properties of ultrahigh molecular weight polyethylene blend fabricated using twin-screw extrusion

2007 ◽  
Vol 107 (5) ◽  
pp. 2837-2845 ◽  
Author(s):  
X. Ren ◽  
X. Q. Wang ◽  
G. Sui ◽  
W. H. Zhong ◽  
M. A. Fuqua ◽  
...  
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

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1333 ◽  
Author(s):  
Olga Mysiukiewicz ◽  
Mateusz Barczewski ◽  
Katarzyna Skórczewska ◽  
Danuta Matykiewicz

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.


2019 ◽  
Vol 49 (8) ◽  
pp. 1011-1035 ◽  
Author(s):  
Fei Wang ◽  
Lichao Liu ◽  
Ping Xue ◽  
Mingyin Jia ◽  
Suwei Wang ◽  
...  

The influence of spinning temperature on ultrahigh-molecular-weight polyethylene/high-density polyethylene as-spun blend filaments and the influence of drawing temperature on ultrahigh-molecular-weight polyethylene/high-density polyethylene-blend fibers were investigated. The results showed that the optimum spinning and hot-drawing temperatures were 310℃ and 85℃, respectively, and blending with high-density polyethylene improved the orienting ability of the molecular chains and the crystallization ability. The blend filaments spun at 310℃ had the best molecular chain orientation, crystallinity and crystal orientation of the filaments examined; both lower and higher spinning temperatures were detrimental to the crystal structure growth of the as-spun blend filaments. The optimum drawing temperature of the blend fibers was 85℃, which resulted in blend fibers with the best molecular chain orientation, crystallization, and crystal orientation as well as the thinnest grains of the fibers examined. The highest tensile strength and initial modulus were 1204 MPa and 20.4 GPa, respectively; these high values can be attributed to the fibrillar structure, which consisted of extended molecular chains and thin grains. The results in this paper can help disclose the effect mechanism of formation temperature on the melt spinning method used to produce high-strength ultrahigh-molecular-weight polyethylene fibers.


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