Stiffness Contribution of Various Wood Fibers to Composite Materials

Abstract

Wood pulp fibers can serve as useful reinforcement of plastics for increased stiffness. To assess the potential of various wood fibers as reinforcement, a method has been developed to determine the contribution of the fibers to the elastic properties of the composite. A micromechanical composite model and classical laminate mechanics are used to relate the elastic properties of the fibers to the elastic properties of the composite. A large variety of composites made of various wood pulp fibers in an epoxy vinyl ester matrix was manufactured. From the tensile test results of the composites, the contributing Young’s moduli of the fibers in the longitudinal direction are back-calculated and summarized. One finding is that there is an optimum in fiber stiffness as a function of lignin content. It is also found that industrially pulped hardwood fibers have higher stiffness than the corresponding softwood fibers. One example is kraft-cooked Norway spruce fiber, for which a Young’s modulus of 40 GPa is found. The effects of hornification, prehydrolysis, and sulfite processing are also investigated. The results indicate that mild defibration process should be used, that does not damage the cell wall structure so that the inherent high stiffness of the native fibers can be retained. It can be concluded that the proposed method works well to rank the wood fiber candidates in terms of their contribution to the composite stiffness.

Macro and micromechanics analysis of short fiber composites stiffness: The case of old newspaper fibers–polypropylene composites

“…For structural and semi structural applications, the most relevant properties are probably stiffness and dimensional stability [23]. Lopez et al [2] found a 1.09 ratio between the Young modulus of 30% glass fiber (GF)-polypropylene and 50% stone groundwood mechanical pulp -polypropylene composites.…”

“…In order to predict the elastic properties of the composite materials it is necessary to know the intrinsic Young's modulus of the fibers, defined as the average slope in the stress-strain curve in the strain interval from 0 to 0.3% [23]. Unfortunately, due to their characteristic morphology, the experimental evaluation of the Young's moduli of ONF is costly and difficult, and sometimes impossible.…”

Correlation Analysis for Fiber Characteristics and Strength Properties of Softwood Kraft Pulps from Different Stages of a Bleaching Fiber Line

“…The contribution of hemicelluloses to fiber strength has been widely discussed and is not entirely clear (Spiegelberg 1966;Schonberg et al 2001). The effect of lignin on tensile strength and tensile stiffness of paper sheets has been reported (Risen et al 2004;Neagu et al 2006). The correlation between the cellulose degradation and fiber strength has also been discussed (Gurnagul et al 1992;Joutsimo et al 2005).…”

Relationship between Strength Properties and Fiber Morphological Characteristics of E. tereticornis

“…The percentage error between the predicted values from the experimental samples for tensile index, tear index, double fold and burst index, were used as the performance criteria of the ANN models. The mean absolute error (MAE), the mean absolute percentage error (MAPE), the root mean square error (RMSE), and correlation coefficient (R²) were used to evaluate the prediction performance of the models [11]. The models yielding the best results for tensile index tear index, burst index and double fold were considered as the prediction models.…”

“…Various research groups have also made efforts to explore the relationship between chemical and physical properties of the pulp fiber and their inherent paper making strength properties. MLR has been used to explore possibility of correlation between morphological features and the strength parameters by various researchers [3][4][5][6][7][8][9][10][11]. Similarly possibility of application of ANN in the paper industry has also been reported in various articles [12][13][14][15][16][17][18] to use neural network based model for prediction of paper properties based on factors related to the most important refining effects, such as the fiber and pulp average length, width and fines content.…”