Effects of process conditions on Young's modulus and strength of extrudate in short-fiber-reinforced polypropylene

2007 ◽  
Vol 28 (1) ◽  
pp. 29-35 ◽  
Author(s):  
Yukio Sanomura ◽  
K. Hayakawa ◽  
M. Mizuno ◽  
M. Kawamura
2014 ◽  
Vol 1621 ◽  
pp. 149-154
Author(s):  
Yukako Oishi ◽  
Atsushi Hotta

ABSTRACTCellulose nanofibers (Cel-F) were extracted by a simple and harmless Star Burst (SB) method, which produced aqueous cellulose-nanofiber solution just by running original cellulose beads under a high pressure of water in the synthetic SB chamber. By optimizing the SB process conditions, the cellulose nanofibers with high aspect ratios and the small diameter of ∼23 nm were obtained, which was confirmed by transmission electron microscopy (TEM). From the structural analysis of the Cel-F/PVA composite by the scanning electron microscopy (SEM), it was found that the Cel-F were homogeneously dispersed in the PVA matrix. Considering the high molecular compatibility of the cellulose and PVA due to the hydrogen bonding, a good adhesive interface could be expected for the Cel-F and the PVA matrix. The influences of the morphological change in Cel-F on the mechanical properties of the composites were analysed. The Young’s modulus rapidly increased from 2.2 GPa to 2.9 GPa up to 40 SB treatments (represented by the unit Pass), whereas the Young’s modulus remained virtually constant above 40 Pass. Due to the uniform dispersibility of the Cel-F, the Young’s modulus of the 100 Pass composite at the concentration of 5 wt% increased up to 3.2 GPa. The experimental results corresponded well with the general theory of the composites with dispersed short-fiber fillers, which clearly indicated that the potential of the cellulose nanofibers as reinforcement materials for hydrophilic polymers was sufficiently confirmed.


Author(s):  
Natalie Rauter ◽  
Rolf Lammering

AbstractIndentation tests are widely used to characterize the material properties of heterogeneous materials. So far there is no explicit analysis of the spatially distributed material properties for short fiber-reinforced composites on the mesoscale as well as a determination of the effective cross-section that is characterized by the obtained measurement results. Hence, the primary objective of this study is the characterization of short fiber-reinforced composites on the mesoscale. Furthermore, it is of interest to determine the corresponding area for which the obtained material parameters are valid. For the experimental investigation of local material properties of short fiber-reinforced composites, the Young’s modulus is obtained by indentation tests. The measured values of the Young’s modulus are compared to results gained by numerical simulation. The numerical model represents an actual microstructure derived from a micrograph of the used material. The analysis of the short fiber-reinforced material by indentation tests reveals the layered structure of the specimen induced by the injection molding process and the oriented material properties of the reinforced material are observed. In addition, the experimentally obtained values for Young’s modulus meet the results of a corresponding numerical analysis. Finally, it is shown, that the area characterized by the indentation test is 25 times larger than the actual projected area of the indentation tip. This leads to the conclusion that indentation tests are an appropriate tool to characterize short fiber-reinforced material on the mesoscale.


2011 ◽  
Vol 55-57 ◽  
pp. 303-307 ◽  
Author(s):  
Bin Zhang ◽  
Bo Qin Gu

In this paper, the stress distribution of short-fiber-reinforced composites (SFRC) using representative volume element (RVE) approach based on the finite element analysis (FEA) was presented. A three-phase model was built, in which loads were applied to the matrix. The influences of interphase parameters like Young’s modulus and thickness were studied. The FEA confirms that interphase Young’s modulus and thickness control stress distribution in SFRC. The stress concentration at the fiber interface becomes greater with high interphase Young’s modulus and thin interphase thickness. The FEA results were also compared with those obtained by analytic method.


2021 ◽  
Vol 138 (27) ◽  
pp. 50648 ◽  
Author(s):  
Roberto Yáñez‐Macías ◽  
Jorge E. Rivera‐Salinas ◽  
Silvia Solís‐Rosales ◽  
Daniel Orduña‐Altamirano ◽  
David Ruíz‐Mendoza ◽  
...  

Author(s):  
Huiyang Luo ◽  
Yanli Zhang ◽  
Bo Wang ◽  
Hongbing Lu

A glass fiber reinforced polyurethane foam (R-PUF), used for thermal insulation of liquefied natural gas tanks, was characterized to determine its compressive strength, modulus, and relaxation behavior. Compressive tests were conducted at different strain rates, ranging from 10−3 s−1 to 10 s−1 using a servohydraulic material testing system, and from 40 s−1 to 103 s−1 using a long split Hopkinson pressure bar (SHPB) designed for materials with low mechanical impedance such as R-PUF. Results indicate that in general both Young’s modulus and collapse strength increase with the strain rate at both room and cryogenic (−170°C) temperatures. The R-PUF shows a linearly viscoelastic behavior prior to collapse. Based on time-temperature superposition principle, relaxation curves at several temperatures were shifted horizontally to determine Young’s relaxation master curve. The results show that Young’s relaxation modulus decreases with time. The relaxation master curve obtained can be used to convert to Young’s modulus at strain rates up to 103 s−1 following linearly viscoelastic analysis after the specimen size effect has been considered.


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