scholarly journals Injection Molding of Wood-Filled Thermoplastic Polyurethane

2021 ◽  
Vol 5 (12) ◽  
pp. 316
Author(s):  
Elmar Moritzer ◽  
Maximilian Richters
Keyword(s):  
Mechanical Properties ◽  
Injection Molding ◽  
Temperature Control ◽  
Fiber Type ◽  
Wood Fiber ◽  
Region Of Interest ◽  
Fiber Reinforcement ◽  
Fiber Content ◽  
Shore Hardness ◽  
Product Price

Wood fiber reinforcement of plastics is almost limited to polypropylene, polyethylene, polyvinyl chloride and polystyrene. Wood fiber reinforcement of thermoplastic polyurethanes (TPU) is a new research field and paltry studied scientifically. Wood fiber reinforcement can carry out synergistic effects between sustainability, material or product price reduction, improved mechanical properties at high elongation, and brilliant appearance and haptics. In order to evaluate to what extent the improvement of mechanical properties depend on material-specific parameters (fiber type, fiber content) and on process-specific parameters (holding pressure, temperature control and injection speed), differently filled compounds were injection molded according to a partial factorial test plan and subjected to characterizing test procedures (tensile test, Shore hardness and notched impact test). Tensile strength showed significant dependence on barrel temperature, fiber type and interaction between holding pressure and barrel temperature in the region of interest. Young’s modulus can be influenced by fiber content but not by fiber type. Notched impact strength showed a significant influence of cylinder temperature, fiber content, fiber type and the interaction between cylinder temperature and fiber content in the region of interest. Shore hardness is related to fiber content and the interaction between mold temperature and injection flow rate. Our results show not only that wood-filled TPU can be processed very well by injection molding, but also that the mechanical properties depend significantly on temperature control in the injection-molding process. Moreover, considering the significant reinforcing effect of the wood fibers, a good fiber-matrix adhesion can be assumed.

scholarly journals Study on Mechanical and Thermal Performance of Building Energy-saving Wall with Insulation Materials

2021 ◽  
Vol 242 ◽  
pp. 02005
Author(s):  
Fuzhen Chen
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Composite Materials ◽  
Energy Saving ◽  
Sodium Alginate ◽  
Natural Fiber ◽  
Wood Fiber ◽  
Building Energy ◽  
Fiber Content ◽  
Building Energy Saving

Sodium alginate and natural fiber were used as modifiers to prepare sodium alginate natural fiber type biological composites. The mechanical properties were characterized by universal testing machine, and the thermal properties were analyzed by conductivity, The effects of wood fiber and straw fiber content on the comprehensive properties of biological composite materials were evaluated by relevant instruments, and the feasibility of biological composite materials as building energy-saving wall insulation materials was evaluated. The results show that the flexural strength, compressive strength and elastic modulus of the composites increase with the increase of wood fiber content. When the wood fiber content is 100%, the mechanical properties of the sample are the best, the flexural strength is 0.573 MPa, and the compressive strength is 1.410 MPa. The results showed that wood fiber and sodium alginate binder were closely combined and had good wettability. The thermal conductivity of biological composite is 0.078-0.089w / (m · K), which means it has good thermal insula tion performance and can be used as thermal insulation material for building energy-saving wall. The results show that the properties of the composite can be improved by adding a higher proportion of wood fiber and a certain amount of glyoxal crosslinking agent.

Synthesis and Characterization of Thermotropic Liquid Crystalline Polyesters/Glass Fiber by In Situ Process

2009 ◽  
Vol 79-82 ◽  
pp. 1435-1438
Author(s):  
Chuan Ji Zhang ◽  
Zhi Xiong Huang
Keyword(s):  
Mechanical Properties ◽  
Glass Fiber ◽  
Optical Microscopy ◽  
Liquid Crystalline ◽  
Mechanical Test ◽  
Fiber Type ◽  
Fiber Content ◽  
Synthesis Process ◽  
Processing Mode ◽  
Mesogenic Unit

Liquid crystalline polyesters containing central biphenylene moiety in the mesogenic unit with ester linkages to the different lengths of flexible spacers were synthesized using melt polycondensation reaction. Glass fiber, as a reinforce, was meltpolymerized with 4-acetoxybenzoic(ABA),4,4＇-diacetoxybiphenyl and terephthalic acid(TA) to make TLCPs with a good mechanical properties. All the obtained compounds were characterized by conventional spectroscopic methods. The thermal behavior of the polymers has been characterized using polarized optical microscopy and differential scanning calorimetry. The effect of monomer structure and mechanical properties has been investigated on the prepared polyesters and is also compared with that of the analogous polyester by other processing mode. Optical microscopy showed a highly threaded liquid crystalline texture to a high birefringent Schlierene texture characteristic of the nematic phase for all polyesters. DSC experiments were also found in accord with mesophase formation. The melting points of polymers having a central 4,4’-biphenyldicarboxylate residue have two broad endotherms. The glass transition temperature values of polyesters are not effect by the glass fiber. According to the SEM result showed that the composite had strong fiber-matrix adhesion. From the mechanical test result, it showed that TLCP are reinforced by rigid fiber further improvement of properties depending on fiber content, fiber fabric construction, fiber type. The mechanical properties of GF/TLCP had been improved greatly as the content of glass fiber was increased,but GF/TLCP mechanical properties do not improve remarkably as glass fiber content more than 30wt%.The effect of copolymerization with added glass fiber in synthesis process is compared with that of the anlogous homopolyesters by other processing mode. Our finding shows that the copolymers exhibit reduced technical process and maintained mechanical properties.

scholarly journals Direct Shear Creep Characteristics and Microstructure of Fiber-Reinforced Soil

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Hao Tang ◽  
Huahua Li ◽  
Zhao Duan ◽  
Chiyang Liu ◽  
Guannan Wu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fiber Reinforcement ◽  
Reinforced Soil ◽  
Fiber Content ◽  
Direct Shear ◽  
Fiber Reinforced ◽  
Creep Tests ◽  
Shear Creep ◽  
Before And After ◽  
Fiber Reinforced Soil

Fiber-reinforced soil is an excellent engineering material that has become a focus of research. Most studies focus on the conventional mechanical properties of reinforced soil, such as its tensile, compressive, and shear strength, and rarely study its creep-related mechanical properties. However, when such soil is used as backfill, the creep effect should not be ignored. This study explored the characteristics of creep mechanics in reinforced soil, the fiber-reinforcement mechanism, and the dynamics of microstructures before and after creep tests. Direct shear creep tests were carried out using a direct shear creep tester on soil reinforced with natural palm fibers of equal length (1.5 cm) in different amounts (0%, 0.2%, 0.6%, 1.0%). Microscale tests were carried out on the reinforced soil samples before and after the creep tests by polarized light and scanning electron microscopy. The results show that the fiber reinforcement can restrain the deformation and enhance the long-term strength of soil. However, a nonlinear relationship between the reinforcement effect and fiber content was found, with 0.6% being the optimal content. Palm fibers have rough surfaces, grooves, and independent pore chambers, which increase the effective contact area and interaction with the soil. With increases in fiber content, the fibers interweave to form a nestled network structure, which increases the strength and integrity of the soil. Fiber addition changes the microstructure of the soil pores; the proportion of large pores decreases and that of small pores increases. Under the effect of creep, the pore changes follow the principle of pore homogenization; large pores are destroyed and transformed into small pores, causing the porosity of reinforced soil to decrease faster and be less porous than unreinforced soil. This research can provide technical reference for the engineering application of palm fiber-reinforced soil.

Mechanical Properties of Glass Fiber Reinforced Polyoxymethylene Composites by Direct Fiber Feeding Injection Molding

2014 ◽  
Author(s):  
Suchalinee Mathurosemontri ◽  
Putinun Uawongsuwan ◽  
Hiroaki Ichikawa ◽  
Hiroyuki Inoya ◽  
Hiroyuki Hamada
Keyword(s):  
Mechanical Properties ◽  
Injection Molding ◽  
Glass Fiber ◽  
Rotational Speed ◽  
Tensile Modulus ◽  
Fiber Content ◽  
Content Increase ◽  
Fiber Reinforced ◽  
Glass Fiber Reinforced ◽  
Feeding Speed

In this study, the short glass fiber reinforced polyoxymethylene composites were fabricated by direct fiber feeding injection molding (DFFIM). The processing parameters such as number of fiber, matrix feeding speed and screw rotational speed are study the effect on fiber content, fiber length and mechanical properties. Fiber orientation and fiber distribution are observed by scanning electron microscope. The maximum and minimum fiber content are 34.1 and 11.5 wt.%, respectively. The increasing of number of fiber and screw rotational speed and the decreasing of matrix feeding speed lead to the increasing of fiber content. Tensile modulus increase when fiber content increase. However, tensile strength do not increase when fiber content is over 23.3 wt.% due to poor orientation and distribution of glass fiber.

scholarly journals Study on External Gas-Assisted Mold Temperature Control with the Assistance of a Flow Focusing Device in the Injection Molding Process

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 965 ◽  
Author(s):  
Nguyen Truong Giang ◽  
Pham Son Minh ◽  
Tran Anh Son ◽  
Tran Minh The Uyen ◽  
Thanh-Hai Nguyen ◽  
...  
Keyword(s):  
Injection Molding ◽  
Temperature Control ◽  
Mold Temperature ◽  
Injection Molding Process ◽  
Melt Flow ◽  
Flow Focusing ◽  
Molding Process ◽  
Heating Efficiency ◽  
Flow Length ◽  
Insert Plate

In the injection molding field, the flow of plastic material is one of the most important issues, especially regarding the ability of melted plastic to fill the thin walls of products. To improve the melt flow length, a high mold temperature was applied with pre-heating of the cavity surface. In this paper, we present our research on the injection molding process with pre-heating by external gas-assisted mold temperature control. After this, we observed an improvement in the melt flow length into thin-walled products due to the high mold temperature during the filling step. In addition, to develop the heating efficiency, a flow focusing device (FFD) was applied and verified. The simulations and experiments were carried out within an air temperature of 400 °C and heating time of 20 s to investigate a flow focusing device to assist with external gas-assisted mold temperature control (Ex-GMTC), with the application of various FFD types for the temperature distribution of the insert plate. The heating process was applied for a simple insert model with dimensions of 50 mm × 50 mm × 2 mm, in order to verify the influence of the FFD geometry on the heating result. After that, Ex-GMTC with the assistance of FFD was carried out for a mold-reading process, and the FFD influence was estimated by the mold heating result and the improvement of the melt flow length using acrylonitrile butadiene styrene (ABS). The results show that the air sprue gap (h) significantly affects the temperature of the insert and an air sprue gap of 3 mm gives the best heating rate, with the highest temperature being 321.2 °C. Likewise, the actual results show that the height of the flow focusing device (V) also influences the temperature of the insert plate and that a 5 mm high FFD gives the best results with a maximum temperature of 332.3 °C. Moreover, the heating efficiency when using FFD is always higher than without FFD. After examining the effect of FFD, its application was considered, in order to improve the melt flow length in injection molding, which increased from 38.6 to 170 mm, while the balance of the melt filling was also clearly improved.

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