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Fiber-gypsum board is a composite material, in which fiber is used as the reinforcement in the matrix of gypsum. The purpose of this research was to investigate the effect of adding different amounts of waste paper fibers on the strength, and the fracture behavior of fiber-gypsum board. For this purpose, zero, 5, 10, 15, 20, 25 and 35 percent gypsum was substituted by waste paper fibers in the mixture. The results of bending strength, internal bonding and moisture absorption after one month exposure to 100% relative humidity measurement showed that increasing the percentage of fibers up to 20% increased the mechanical properties. In general, using twenty percent fibers in the mixture increased the bending strength by 50% and the internal bonding was increase two and half times compared to the control samples. The load-displacement curve shows that the dosage of 5 to 15 percent of fibers does not change the fracture behavior of the fibergypsum board and exhibited brittle fracture as in control samples. While at higher dosage, the flexibility increases and the failure becomes ductile. Therefore, the best conditions in terms of strength, resistance, and flexibility was reached at 20% substitution of gypsum with waste paper fibers. [ABSTRACT FROM AUTHOR]

In this study, the reinforcing effect of recycled newsprint paper (RNP) in cement boards has been investigated. The experiment was designed to apply two variable factors, RNP and calcium chloride (CaCl2). Cement-fiber boards with the density of 0.7 kg/m3 were manufactured using fiber/cement ratios of 10:90, 15:85, 20:80 and 25:75 (w/w) and 3% and 5% CaCl2 as accelerator. Minimum four boards (replications) were fabricated for each combination of variables, and the mechanical and physical properties of the boards were evaluated. The statistical analysis showed that the effect of the RNP and CaCl2 contents on modulus of rupture of cement fiber boards were significant at 1% significant level. The results showed that addition of CaCl2 enhanced the mechanical properties of the boards. All properties of the boards were improved as the CaCl2 content was increased from 3% to 5%. The modulus of rupture and modulus of elasticity of the boards decreased with addition of RNP, and the maximum values were obtained at RNP loading of 10%. The results also showed that as the fiber content was increased, significant increase in water absorption and thickness swelling occurred. Increasing RNP fiber content from 10% to 25% reduced both the mechanical and physical properties considerably. The optimum condition was obtained when the RNP and CaCl2 contents were 10% and 5%, respectively.

In this study, the effect of nanoclay particles and coupling agent on the physical and mechanical properties of polypropylene / waste paper composites was studied. To meet this objectives, waste paper fibers with polypropylene in 50% by weight, nanoclay (0, 2 and 4%) and coupling agent (0 and 3%) were compounded in an internal mixer at 155°C and 60rmp and the samples were prepared by injection molding. The results showed that the physical and mechanical strength of composite improved in the presence of coupling agent. As well as water absorption, thickness swelling, flexural and tensile strength and flexural and tensile modulus, were improved by increasing of nanoclay particles content, however notched impact strength was reduced. Also, study on structural behavior of composite with x-ray diffraction showed that nanoclay distributed as intercalation structure in polymer matrix, and distance between layers were increased with increasing of nanoclay particles content.

This study was conducted to investigate the potential of waste newspaper application in cement fiber board production. Cement fiber board were produced using three levels of waste paper fibers and two levels of calcium chloride as additive material. After making the boards, the Modulus of Rupture (MOR) and thickness swelling after 24 hours immersion in water were determined based on DIN 68763. The results showed that boards made with cement:fiber ratio 90:10 and 5% calcium chloride exhibited the maximum modulus of rupture and minimum of thickness swelling (TS) after 24 hours. The results also showed that additive material had positive effect on physical and mechanical properties of boards.

Utilization of date palm and kenaf fibers for reinforcement of plywood was investigated and after making plywood with layers of horn beam wood (Carpinus betulus), physical and mechanical properties were analyzed. Variables were the type of fiber (kenaf and date palm), the type of filler (wheat flour and waste paper) and the content of resin (150 and 200 g/m2). The results of this study show that utilization of kenaf and date palm fibers was effective in improvement of physical and mechanical properties of plywood. The mean of specific gravity for reinforced plywood with kenaf and date palm fibers was 0.723 and 0.739 g/cm3 respectively and specific gravity of control was 0.656 g/cm3. The least water absorption and thickness swelling were about reinforced boards with kenaf fibers and 200 g/m2 resin with wheat flour filler .The reinforced boards with kenaf fibers and 150g/m2 resin with wheat flour filler have the best mechanical properties. So the kenaf fibers for reinforcement of properties of plywood were better than date palm fibers and the utilization of wheat flour in manufacture of these boards had better results compared to waste paper filler.

The possibility waste paper (writing paper and newsprint) and old corrugated carton (OCC) utilization as a filler of urea formaldehyde resin onplywood manufacturing was investigated. Theeffect of type of filler as a variable factor on applicable properties i.e. water absorption and swelling after 2 and 24 hours, bending strength parallel and perpendicular to grain and shear strength on the interface was evaluated and the results were analyzed. The results of this study showed that utilization of waste paper and old corrugated carton as the filler decreased the water absorption and swelling and improved their mechanical properties. Since this materials caused to promote adhesion and improved the urea formaldehyde resin bond, it can be inferred that waste paper and old carton can act as an extender on the resin binding process.