Alireza Asgari; Amirhooman Hemmasi; Behzad Baziyar; Mohammad Talaeipour; Amir Nourbakhsh
Abstract
The mechanical (tensile strength and modulus, bending strength and modulus), humidity (water absorption and thickness swelling) and biodegradability properties of wood-plastics produced from polypropylene and poplar wood-flour (wood flour in three levels of 0, 20 and 25 percentage) in the presence of ...
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The mechanical (tensile strength and modulus, bending strength and modulus), humidity (water absorption and thickness swelling) and biodegradability properties of wood-plastics produced from polypropylene and poplar wood-flour (wood flour in three levels of 0, 20 and 25 percentage) in the presence of starch powder (at four levels of 0, 5, 10 and 15 percentage) are assessed as a bio strength agent. The material mixing process is run in two stages of applying an extruder machine and applying an internal mixer haake machine. The mechanical and humidity tests specimens are produced by mold injection method and the biodegradability test specimens are formed by hot press method. The tests are run according to standards and procedures. The results indicate that an increase in weight percentage of wood-flour in the composition, increase the mechanical strength, water absorption, thickness swelling and biodegradability of composites. An increase in weight percentage of starch powder in the composition, increase the bending strength and modulus, tensile modulus, water absorption, thickness swelling and biodegradability of composites, while decreasing the tensile strength. Additional studies run through the scanning electron microscopy indicate that by adding wood-flour and starch powder to the composition, the intensity of biodegradation increase at the surface of the specimens. By adding starch powder to the composition, the starch powder particles fill the cavities in the composite structure, thus a reduction in the volume of the pores in the composite structure.
Mojtaba Asadi; Behzad Bazyar; Amir Hooman Hemmasi; Mohammad Talaeipour; Ismail Ghasemi
Abstract
AbstractThe paper aims to study differential, dynamic-mechanical and biodegradability analysis of polylactic acid/wood fiber (PLA) composites using three levels of nano-graphene (0.75, 1.5 and 3%). In order to mix the materials together and to make standard specimens, an internal mixer and pressure press ...
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AbstractThe paper aims to study differential, dynamic-mechanical and biodegradability analysis of polylactic acid/wood fiber (PLA) composites using three levels of nano-graphene (0.75, 1.5 and 3%). In order to mix the materials together and to make standard specimens, an internal mixer and pressure press were used. In the analysis of differential polishing calorimeter, the addition of fibers as well as nano-graphene had a positive effect on the glass transition temperature and the degree of crystallinity, which indicates a change from softness and flexibility to hardness and hardness. Dynamic-mechanical analysis has shown that the addition of wood fibers to pure polylactic acid can case an increase in the storage modulus of the composite and with the addition of nano-graphene to increasing composition, while the highest amount of storage modulus was related to polylactic acid composites / 30% of fibers and 30% of fibers. Results of tan δ peak showed that with the presence of wood fibers and nano-graphene, the temperature was transferred to a higher temperature and the limited movement of molecules due to the improvement of the fiber reaction in the PLA polymer. The results of biodegradability test also showed that the addition of fibers to pure PLA caused a significant increase in the weight loss of the composite. Additionally, nano-graphene to PLA composites decreases with the less weight in composites.
Composite wood products
Moein Dehghan; Ali Ahmadi ladjimi; Habib Dahmardeh
Abstract
DOR:98.1000/1735-0913.1398.34.63.66.1.1575.1610 In the present research the biodegradability Properties of poly-lactic acid-canola stem flour composites in three levels of 25, 35, and 45% canola stem flour made by compression molding technique were studied . In order to study the biocompatibility behavior ...
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DOR:98.1000/1735-0913.1398.34.63.66.1.1575.1610 In the present research the biodegradability Properties of poly-lactic acid-canola stem flour composites in three levels of 25, 35, and 45% canola stem flour made by compression molding technique were studied . In order to study the biocompatibility behavior of the composite, three methods of biological degradation were used for Trametes versicolor and Gloeophyllum trabeum fungi, long-term water absorption and composites burial in the soil for 4 months. The results of statistical analyzes showed that the amount of composites weight loss increased against the degradation by fungi and burial in the soil by increasing the amount of rapeseed canola stem flour while pure poly-lactic acid had a very high durability against these factors. In addition, there was no effect on the weight loss of samples in the long run leach test so that the weight of composites and poly- lactic acid samples was constantly increasing and there was no effect on weight and thickness loss. The growth of myceliums fungi was clearly detectable and detectable in reviewing the images of electron microscopy from the fracture properties of composites, unlike poly-lactic acid so that fungi crossed their polymer into rapeseed shoot flour and reduced the weight of the composites. The results of the FTIR spectroscopy on poly-lactic acid prepared before and after exposure to the Gloeophyllum trabeum fungus confirmed the validity of the above results. According to the results of this study, poly-lactic acid, as a biodegradable polymer, has been shown to be very durable against degradation by natural biological agents.
Composite wood products
Shoboo Salehpour; Mehdi Jonobi; Masoud Ahmad Zadeh; Fatemeh Rafieian
Abstract
The biodegradability of cellulose nananofiber-PVA nanocomposites were studied under controlled composting conditions and the quality of the compost was evaluated. The nanocomposite based on PVA with 5, 10, 20 and 30 wt % of CNF was prepared by using liquid nitrogen and freeze drying techniques. Specimens ...
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The biodegradability of cellulose nananofiber-PVA nanocomposites were studied under controlled composting conditions and the quality of the compost was evaluated. The nanocomposite based on PVA with 5, 10, 20 and 30 wt % of CNF was prepared by using liquid nitrogen and freeze drying techniques. Specimens were buried in compost obtained from municipal solid waste of a compost Factory, Karaj municipality, Iran, for 150 days. The biodegradability of materials was assessed by calculation the visual observation, weight loss, scanning electron microscopy (SEM) and chemistry and transparency (FTIR). The ecotoxicological impact of compost samples was evaluated via plant growth tests with cress and spinach. Biodegradation studies of the films during municipal solid waste confirmed that the biodegradation time of PVA/CNF films greatly depends on the CNF content. The SEM analysis showed that the biodegradability of the films at surface of the samples (deep pores and cracks) was increased with increased the CNF content. By considering the ecotoxicological test using plants growth, it seems that all nanocomposite and pure PVA did not generate a negative effect on germination or development of the vegetal species.
