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Qualitative and Strength Analysis of Pine (Pinus Sylvestris L.) Wood Materials - Study of Pallet Elements
The manufacture of packaging products requires determining the strength requirements of the components that make up the structural elements of pallets, crates and other packaging. Wood, as a renewable material, is the basic raw material for manufacturing wooden pallets. The premise of the research is that the strength of pallets is derived from the characteristics of the components of the subassemblies. Strength tests of lumber were carried out, which determine the evaluation of the suitability of sawn materials. Verification of raw material properties determines the adaptation of individual assemblies to static and dynamic force loads. Pine (Pinus sylvestris L.) lumber was verified, taking into account the origin of the cross-sectional area and the presence of anatomical structure features. The results of the study confirm the influence of wood origin on the suitability of pine wood for wood packaging. The influence of a certain origin from the log can translate into changes in strength properties. It was found that wood density is not a critical parameter for evaluating the strength of lumber and product. Tests of separated structural lumber for wood packaging indicate significant differences in the condition of the wood and the magnitude of the strength parameter.
Properties of fiber-gypsum composite formed on the basis of hemp (Cannabis sativa L.) fibers grown in Poland and natural gypsum
: Properties of fiber-gypsum composite formed on the basis of hemp (Cannabis sativa L.) fibers grown in Poland and natural gypsum. The popularity of composites reinforced with natural fibers is constantly growing and therefore, they are a subject of many scientific works as well. An example of interesting concept is the use of hemp fibers to reinforce a gypsum matrix and therefore, presented study was aimed to determine the effect of their content on the properties of resultant composites. Moreover, the influence of setting temperature was also investigated. The scope of the research included determination of properties such as: density, setting time, bending strength, modulus of elasticity and thermal conductivity coefficient. Studies have shown that as the amount introduced fibers increases, the density of manufactured composites decreases. Furthermore, increase in the content of hemp causes a significant extension in setting time of the gypsum matrix. Based on the outcomes of mechanical properties, it was found that the optimal content of fibers is 4% and further increase in their share results in a deterioration of flexural strength characteristics. The increase in a setting temperature leads to thereduction in their bending strength and modulus of elasticity. Composites reinforced with hemp fibers demonstrate significantly improved thermal insulation properties
Physico-Mechanical Characteristics of Gypsum–Fiber Boards Manufactured with Hydrophobically Impregnated Fibers
Although gypsum-based building materials exhibit many positive characteristics, solutions are still being searched for to reduce the use of gypsum or improve the physico-mechanical properties of board materials. In this study, an attempt was made to produce gypsum boards with hemp fibers. Although hemp fibers can be a specific reinforcement for gypsum-based board materials, they negatively affect the gypsum setting process due to their hygroscopic characteristics. Fibers impregnated with derivatives based on polyvinyl acetate, styrene–acrylic copolymer and pMDI (polymeric diphenylmethane diisocyanate) were used in this study. Gypsum–fiber boards produced with impregnated fibers showed approximately 30% higher mechanical properties as determined by the 3-point bending test. The positive effect of the impregnates on the hemp fibers was confirmed by FTIR (Fourier-transform infrared spectroscopy) and TG/DTA (thermogravimetric analysis/thermal gravimetric analysis) analysis.
The Influence of Hemp Fibers (Cannabis sativa L.) on the Mechanical Properties of Fiber–Gypsum Boards Reinforcing the Gypsum Matrix
The modern construction industry is looking for new ecological materials (available, cheap, recyclable) that can successfully replace materials that are not environmentally friendly. Fibers of natural origin are materials that can improve the properties of gypsum composites. This is an important issue because synthetic fibers (hardly biodegradable—glass or polypropylene fibers) are commonly used to reinforce gypsum boards. Increasing the state of knowledge regarding the possibility of replacing synthetic fibers with natural fibers is another step towards creating more environmentally friendly building materials and determining their characteristics. This paper investigates the possibility of manufacturing fiber–gypsum composites based on natural gypsum (building gypsum) and hemp (Cannabis sativa L.) fibers grown in Poland. The effect of introducing hemp fibers of different lengths and with varying proportions of mass (mass of gypsum to mass of fibers) into the gypsum matrix was investigated. The experimental data obtained indicate that adding hemp fibers to the gypsum matrix increases the static bending strength of the composites manufactured. The highest mechanical strength, at 4.19 N/mm2, was observed in fiber–gypsum composites with 4% hemp fiber content at 50 mm in length. A similar trend of increased strength was observed in longitudinal tension. Again, the composite variant with 4% fiber content within the gypsum matrix had the highest mechanical strength. Manufacturing fibers–gypsum composites with more than 4% hemp fiber content negatively affected the composites’ strength. Mixing long (50 mm) hemp fibers with the gypsum matrix is technologically problematic, but tests have shown a positive effect on the mechanical properties of the refined composites. The article indicates the length and quantity limitations of hemp fibers on the basis of which fiber–gypsum composites were produced.
The Optimization of the Strength of Wood Adhesive Joints Supported by Steel Fasteners in Furniture Components
The strength properties of softwood components with bonded joints reinforced with fasteners were investigated and compared. Initial tests of the strength of the glue joints were carried out, with a change in the type of adhesive used. The application method significantly influenced the shear strength of the joint. With the adhesive and pre-bonding systems used, the shear strength of the adhesive joint of pine wood (Pinus silvestris L.) with PUR and PVAC resin was determined. The industrial results were 31% lower than in the shear test of the wooden joint bonded with PVAC glue. In terms of transverse shear force with staples, the joint has a transverse holding force that is higher than components connected with screws or nails. As the number of glue sticks increased, the shear strength of the pine wood increased. The strengths of the joined components in the glue roller method had an intermediate value. They did not differ significantly between the two-row gluing systems used. An increase in the force required to shear the bonded joint was observed for the different adhesive systems, the fasteners used, and their density.
Influence of pine wood sawing technology on material efficiency indicators
Influence of pine wood sawing technology on material efficiency indicatorsConiferous wood processing is one of the basic methods of using natural wood resources. The aim of the work was to determine the impact of the selection of wood cutting technology, which plays an important role in shaping the material indices, especially the volumetric efficiency index. In the case of pine wood processing, group and individual technologies were assessed.. The use of frame saws guarantees the achievement of repeated sorting’s with a quantitative efficiency rate of 69%. The introduction of individual technology based on band saws results in an increase in quantitative sawing efficiency to 72%. The selection of processing technology and the dimensional structure of processed roundwood have a significant impact on the average sawing rate.