Processing of short fiber reinforced polypropylene. II: Statistical study of the effects of processing conditions on the impact strength

1999 ◽  
Vol 39 (10) ◽  
pp. 1880-1890 ◽  
Author(s):  
Silvia E. Barbosa ◽  
Jos� M. Kenny
2011 ◽  
Vol 31 (2-3) ◽  
Author(s):  
Omid Moini Jazani ◽  
Ahmad Arefazar ◽  
Seyyed Hassan Jafari ◽  
Mohammad Reza Saeb

Abstract In this study, nine ternary blends of polypropylene (PP)/poly [styrene-b-(ethylene-co butylene)-b-styrene] tri-block copolymer (SEBS)/polycarbonate (PC) were produced at different processing conditions through twin screw extruder. Accordingly, die temperature, screw speed, and blending sequences were altered based on L9 Taguchi experimental design as indications of processing variables. Consequently, the impact strength of each produced sample is considered as the responding variable. Analyzing two important aspects, namely main and interactive effects by using Taguchi analysis, was the especial point of view in our contribution; as a result, not only was the PP/SEBS/PC ternary system studied for the first time, but the SEBS-g-MAH compatibilizer also showed sufficient effects on morphology development. It was observed that the impact strength of PP/SEBS/PC ternary blends is not affected by die temperature significantly, whereas screw speed and blending sequence have had effective impacts. Besides, the optimum processing condition, which is proportional to the highest value of impact strength, is recommended through the mentioned ternary blends. These results are also confirmed while applying image analysis on morphology micrographs.


2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Nina Graupner ◽  
Jörg Müssig

The present study focuses on a comparison between different cellulose fiber-reinforced thermoplastics. Composites were produced with 30 mass-% lyocell fibers and a PLA or PP matrix with either an injection (IM) or compression molding (CM) process. Significant reinforcement effects were achieved for tensile strength, Young’s modulus, and Shore D hardness by using lyocell as reinforcing fiber. These values are significantly higher for PLA and its composites compared to PP and PP-based composites. Investigations of the fiber/matrix adhesion show a better bonding for lyocell in PLA compared to PP, resulting in a more effective load transfer from the matrix to the fiber. However, PLA is brittle while PP shows a ductile stress-strain behavior. The impact strength of PLA was drastically improved by adding lyocell while the impact strength of PP decreased. CM and IM composites do not show significant differences in fiber orientation. Despite a better compaction of IM composites, higher tensile strength values were achieved for CM samples due to a higher fiber length.


Fibers ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 64
Author(s):  
Roman Fediuk ◽  
Mugahed Amran ◽  
Sergey Klyuev ◽  
Aleksandr Klyuev

The use of fiber in cement materials is a promising and effective replacement for bar reinforcement. A wide range of fiber-reinforced concretes based on composite binders with increased impact strength characteristics have been developed. The synthesized composites included the composite binder made of Portland cement, silica, and carbonate additives. Basalt and steel were used as fibers. The nature of the influence of the composition and manufacturing technology of cement composites on the dynamic hardening coefficient has been established, while the growth of these indicators is achieved by creating a denser interfacial transition zone between the cement paste, aggregate, and fiber as a result of improving the homogeneity of the concrete mixture and controlling the consistency. Workability indicators (slump flow up to 730 mm; spreading time up to a diameter of 50 cm is up to 3 s) allow them to be classified as self-compacting concrete mixtures. An increase in the values of the impact strength coefficient by a factor of 5.5, the dynamic hardening coefficient by almost 70% as a result of interfacial interaction between fibers and binder matrix in the concrete composite, as well as absorption of impact energy by fiber, was revealed. The formula describing the effect of the loading rate on the coefficient of dynamic hardening of fiber-reinforced concrete has been refined. The fracture processes of the obtained materials have been established: after the initiation of primary cracks, the structure of the composite absorbs impact energy for a long time, while in the inelastic range (the onset of cracking and peak loads), a large number of secondary cracks appear.


2017 ◽  
Vol 21 ◽  
pp. 219-225 ◽  
Author(s):  
Gerardo Araya-Letelier ◽  
Federico C. Antico ◽  
Pablo Fernado Parra ◽  
Miguel Carrasco

Recycled fibers from food-industry could be added as reinforcement to cement-based materials. Cement-based materials perform well under compression, but tensile strength and post-cracking ductility in tension are poor. Fibers produced from steel, glass and synthetic materials, have been successfully used to overcome some of these shortcomings. Fiber-reinforced mortar has shown an increased post-cracking ductility and improved long-term serviceability due to the crack control provided by fibers. Food-industry waste disposal is globally a major concern because of its environmental impacts. For these reasons, the use of recycled materials in construction applications has been investigated over the last decades. This investigation deals with the incorporation of pig hair, which is a waste produced by the food-industry worldwide, in fiber-reinforced mortars. This composite material is intended to reduce the environmental impacts by valuing waste materials in construction applications while improving mechanical properties. To determine compressive, flexural and impact strength, bulk density, porosity and dynamic modulus of elasticity laboratory tests were conducted in mortar specimens with 0%, and 2% of pig-hair content in weight of cement. The results of this research show that the impact strength can increase up to five times when compared to plain mortar. Moreover, the compressive and flexural strengths, bulk density, porosity and the dynamic modulus of elasticity of fiber-reinforced mortar, with the aforementioned pig-hair content, are not significantly affected.


Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1079 ◽  
Author(s):  
David Hernández-Díaz ◽  
Ricardo Villar-Ribera ◽  
Francesc X. Espinach ◽  
Fernando Julián ◽  
Vicente Hernández-Abad ◽  
...  

Natural fiber-reinforced thermoplastic composites can be an alternative to mineral fiber-based composites, especially when economic and environment concerns are included under the material selection criteria. In recent years, the literature has shown how lignocellulosic fiber-reinforced composites can be used for a variety of applications. Nonetheless, the impact strength and the water uptake behavior of such materials have been seen as drawbacks. In this work, the impact strength and the water uptake of composites made of polypropylene reinforced with fibers from recycled newspaper have been researched. The results show how the impact strength decreases with the percentage of reinforcement in a similar manner to that of glass fiber-reinforced polypropylene composites as a result of adding a fragile phase to the material. It was found that the water uptake increased with the increasing percentages of lignocellulosic fibers due to the hydrophilic nature of such reinforcements. The diffusion behavior was found to be Fickian. A maleic anhydride was added as a coupling agent in order to increase the strength of the interface between the matrix and the reinforcements. It was found that the presence of such a coupling agent increased the impact strength of the composites and decreased the water uptake. Impact strengths of 21.3 kJ/m3 were obtained for a coupled composite with 30 wt % reinforcement contents, which is a value higher than that obtained for glass fiber-based materials. The obtained composites reinforced with recycled fibers showed competitive impact strength and water uptake behaviors in comparison with materials reinforced with raw lignocellulosic fibers. The article increases the knowledge on newspaper fiber-reinforced polyolefin composite properties, showing the competitiveness of waste-based materials.


2015 ◽  
Vol 773-774 ◽  
pp. 48-52
Author(s):  
Al Emran Ismail

This present work investigated the perforated impact strength of woven kenaf fiber reinforced composites subjected to different projectile velocities. Three layers of woven kenaf mats were stacked with four different fiber orientations 0, 15, 30 and 450. The composites are fabricated using hand-layout where the woven mats were placed into the mould with a polymeric resin. The wetted composites were compressed to squeeze out the excessive resin and to eliminate the void contents. The hardened samples were shaped into a standard geometry specified by ASTM D3763. Then, the composites were perforated impact using different speeds 1, 2 and 3 m/s. According to the present results, it was found that the perforated impact strength reduced when the impact velocity was increased. However, the impact strength of 150 oriented composite was higher when compared with other types of composites.


Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2144
Author(s):  
Helena Oliver-Ortega ◽  
Quim Tarrés ◽  
Pere Mutjé ◽  
Marc Delgado-Aguilar ◽  
José Alberto Méndez ◽  
...  

The research toward environmentally friendly materials has devoted a great effort on composites based on natural fiber-reinforced biopolymers. These materials have shown noticeable mechanical properties, mainly tensile and flexural strengths, as a consequence of increasingly strong interfaces. Previous studies have shown a good interface between natural fibers and poly (lactic acid) (PLA) when these fibers present a low lignin content in their surface chemical composition (bleached fibers). Nonetheless, one of the main drawbacks of these materials is the hydrophilicity of the reinforcements in front of the mineral ones like glass fiber. Meanwhile, the behavior of such materials under impact is also of importance to evaluate its usefulness. This research evaluates the water uptake behavior and the impact strength of bleached Kraft softwood-reinforced PLA composites that have been reported to show noticeable tensile and flexural properties. The paper explores the differences between these bio-based materials and commodity composites like glass fiber-reinforced polypropylene.


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