Effect of short basalt fibers on durability, mechanical properties, and thermal properties of polylactic acid composites

The effect of basalt fiber (BF) content on the properties of BF-reinforced polylactic acid (PLA) composites was investigated. Composites with 10, 20, 30, 40, 50, and 60 wt% BF were fabricated. The results revealed that (1) the mechanical properties improved with increasing BF content. The maximum tensile strength and modulus of the composites (i.e. 140 and 5050 MPa, respectively) occurred at a BF content of 50%. The maximum flexural strength, that is, 159.5 MPa was two times larger than that of the pure PLA and was obtained at a BF content of 40%. However, the mechanical properties deteriorated at BF contents >50%. (2) BF can stop storage modulus loss and are effective in improving the crystallinity, as revealed by dynamic mechanical analysis and differential scanning calorimetry measurements. The crystallinity improved from 34.6% to 54.6% with BF addition. (3) After the accelerated aging test, pure PLA was too weak for testing. However, high values of the tensile modulus (i.e. 60% that of the nonaged samples) were maintained by the BF-reinforced PLA. This resulted possibly from the high crystallinity of the PLA composites. Therefore, suitable amounts of BF as reinforcements can yield improvements in the performance of PLA composites.

Download Full-text

Physico Chemical Characterization of Nanofibrous Poly(Ε-Caprolactone) Electrospun Templates for Cell Adhesion

MRS Advances ◽

10.1557/adv.2017.529 ◽

2017 ◽

Vol 2 (49) ◽

pp. 2689-2694

Author(s):

Karla A. Gaspar-Ovalle ◽

Juan V. Cauich-Rodriguez ◽

Armando Encinas

Keyword(s):

Mechanical Properties ◽

Differential Scanning Calorimetry ◽

Cell Adhesion ◽

Tensile Modulus ◽

Chemical Characterization ◽

Mechanical Analysis ◽

Scanning Calorimetry ◽

Water Contact ◽

Physico Chemical ◽

Static Water

ABSTRACTNanofibrous mats of poly ε-caprolactone (PCL) were fabricated by electrospinning. The nanofiber structures were investigated and characterized by scanning electron microscope, differential scanning calorimetry, thermogravimetric analysis, dynamic mechanical analysis, static water-contact-angle analysis and mechanical properties. The results showed that the nanofibrous PCL is an ideal biopolymer for cell adhesion, owing to its biocompatibility, biodegradability, structural stability and mechanical properties. Differential scanning calorimetry results showed that the fibrous structure of PCL does not alter its crystallinity. Studies of the mechanical properties, wettability and degradability showed that the structure of the electrospun PCL improved the tensile modulus, tensile strength, wettability and biodegradability of the nanotemplates. To evaluate the nanofibrous structure of PCL on cell adhesion, osteoblasts cells were seeded on these templates. The results showed that both adhesion and proliferation of the cells is viable on these electrospun PCL membranes. Thus electrospinning is a relatively inexpensive and scalable manufacturing technique for submicron to nanometer diameter fibers, which can be of interest in the commodity industry.

Download Full-text

Effect of Melamine Content in MUF Resin on the Durable Properties of Plywood

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.71-78.3160 ◽

2011 ◽

Vol 71-78 ◽

pp. 3160-3164 ◽

Cited By ~ 3

Author(s):

Xiao Ying Liu ◽

Ji Zhi Zhang ◽

Yong Lin Yang ◽

Shi Feng Zhang ◽

Jian Zhang Li

Keyword(s):

Mechanical Properties ◽

Ammonium Chloride ◽

Urea Formaldehyde ◽

Accelerated Aging ◽

Formaldehyde Emission ◽

Acidic Condition ◽

Uf Resin ◽

Accelerated Aging Test ◽

Aging Test ◽

Modified Urea

The effect of melamine content in melamine modified urea formaldehyde (MUF) resin on durable properties of plywood was investigated using ammonium chloride (NH4Cl) with different melamine/urea (M/U) ratios. The plywood specimens were exposed to laboratory accelerated aging and/or cyclic soak-dry (SD). The experiment results indicated that the melamine contents in MUF resin showed an unobservable effect on the durable properties of MUF resin bonded plywood. The mechanical properties of plywood decreased more severely after accelerated aging test in acidic condition. However, the influence of different curing catalyst contents on mechanical properties and formaldehyde emission of UF resin can be minimized by adding melamine to the resin.

Download Full-text

The Influence of the Accelerated Aging Conditions on the Properties of Polyolefin Geogrids Used for Landfill Slope Reinforcement

Polymers ◽

10.3390/polym12091874 ◽

2020 ◽

Vol 12 (9) ◽

pp. 1874

Author(s):

Agnieszka Kiersnowska ◽

Wojciech Fabianowski ◽

Eugeniusz Koda

Keyword(s):

Mechanical Properties ◽

Relative Elongation ◽

Oxidative Degradation ◽

Accelerated Aging ◽

Melt Flow Index ◽

Flow Index ◽

Scanning Calorimetry ◽

Oxidation Induction Time ◽

Aging Test ◽

Different Temperatures

Polyolefin geosynthetics are susceptible to oxidative degradation, which in turn leads to diminished mechanical properties in geotechnical constructions. When using these materials, it is extremely important to determine their durability over time in particularly aggressive conditions. In order to prolong the life of a geosynthetic material, antioxidants are added during the manufacturing process. The function of antioxidants is to prevent polymer oxidation reaction in time. As the antioxidant content is depleted, the polymer becomes less protected towards oxidative attacks. This article describes the aging process of uniaxial (high density polyethylene) HDPE geogrids under the influence of chemical and environmental factors. Evaluations of accelerated aging test of the uniaxial HDPE geogrids were incubated in simulated landfill conditions for a period of 12 months. Three temperatures (25 °C, 45 °C, and 75 °C) were selected for carrying out the aging experiments in aqueous solutions mimicking landfill conditions. The changes observed by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR) and melt flow index (MFI) correlate with the mechanical properties of the aged geogrid. No significant changes in the FTIR and MFI were observed over the 12 months of accelerated aging tests at none of the three different temperatures. The oxidation induction time (OIT) test showed no antioxidant remaining in the geogrid following eight months of aging test at 75 °C. No significant changes in the influence of accelerated aging tests on the average relative elongation at 25 °C and 45 °C of the tested material were observed. Accelerated aging tests at 75 °C showed that the mean elongation of 12.12% for the sample not subjected to accelerated aging tests (new sample) increased to 19.32% (after 12 months of incubation).

Download Full-text

Correlation between Alternating Temperature Accelerated Aging and Real World Storage of Composite Propellant

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.525-526.421 ◽

2012 ◽

Vol 525-526 ◽

pp. 421-424

Author(s):

Biao Ding ◽

Pei Shi ◽

Xin Qiu

Keyword(s):

Mechanical Properties ◽

Real World ◽

Accelerated Aging ◽

Solid Rocket Motor ◽

Composite Propellant ◽

Accelerated Aging Test ◽

Aging Test ◽

Htpb Propellant ◽

Alternating Temperature ◽

Solid Rocket

Alternating temperature accelerated aging test was designed to ensure that accelerated aging could preferably simulate real world storage of HTPB composite propellant. Mechanical properties of HTPB propellant aged for three different periods were measured and analyzed. The results indicate that, the tensile strength increased and the elongation decreased after accelerated aging, showing the same trend of real world storage; the mechanical properties of HTPB propellant is strongly influenced by the rate of temperature change; alternating temperature accelerated aging test is consistent well with real world storage. The results can be very helpful for solid rocket motor life prediction.

Download Full-text

EFFECT OF HUMIDITY ON THE MECHANICAL PROPERTIES OF KENAF YARN FIBRE/POLYLACTIC ACID BIOCOMPOSITES

Jurnal Teknologi ◽

10.11113/jt.v81.13602 ◽

2019 ◽

Vol 81 (5) ◽

Author(s):

Meor Syazalee ◽

Rozli Zulkifli

Keyword(s):

Mechanical Properties ◽

Relative Humidity ◽

Polylactic Acid ◽

Mechanical Performance ◽

Flexural Modulus ◽

Tensile Modulus ◽

Mechanical Analysis ◽

Natural Fibre ◽

Static Mechanical ◽

And Storage

Humidity during the fabrication of natural fibre reinforced composites can harm their mechanical performance. This study examines the effect of humidity during the fabrication of unidirectional kenaf/polylactic acid (PLA) biocomposites on their dynamic and static mechanical properties. Kenaf fibres were conditioned at different relative humidity (RH) levels (40% RH, 60% RH and 80% RH) before being pressed with PLA to form biocomposites. Kenaf/PLA biocomposites were analysed using dynamic mechanical analysis, fracture toughness in mode II, tensile and flexural. Results indicated that the value of GIIC and storage modulus decreased when the relative humidity increased. Reduced tensile and flexural modulus were observed when kenaf was exposed to high relative humidity of 80% RH. However, the form of unidirectional kenaf affected the properties and reduced the drop value in the tensile modulus. The optimum relative humidity to produce kenaf/PLA biocomposites is 40% RH.

Download Full-text

Understanding the degradation process of polyhydroxyalkanoate (PHA)/ poly(butylene adipate-co-terephthalate) (PBAT) biocomposite mulch films and the effects of stabilizers under accelerated aging test

10.1021/scimeetings.0c03211 ◽

2020 ◽

Author(s):

Yuchuan Tian ◽

Bing Zhou ◽

James H. Wang

Keyword(s):

Accelerated Aging ◽

Degradation Process ◽

Accelerated Aging Test ◽

Aging Test ◽

Mulch Films

Download Full-text

Influence of Treated Distillate Aromatic Extract (TDAE) Content and Addition Time on Rubber-Filler Interactions in Silica Filled SBR/BR Blends

Polymers ◽

10.3390/polym13050698 ◽

2021 ◽

Vol 13 (5) ◽

pp. 698

Author(s):

Selin Sökmen ◽

Katja Oßwald ◽

Katrin Reincke ◽

Sybill Ilisch

Keyword(s):

Mechanical Properties ◽

Oil Content ◽

Tensile Modulus ◽

Mechanical Analysis ◽

Styrene Butadiene Rubber ◽

Butadiene Rubber ◽

Binary Blends ◽

Rubber Layer ◽

Processing Aids ◽

Rubber Filler

High compatibility and good rubber–filler interactions are required in order to obtain high quality products. Rubber–filler and filler–filler interactions can be influenced by various material factors, such as the presence of processing aids. Although different processing aids, especially the plasticizers, and their effects on compatibility have been investigated in the literature, their influence on rubber–filler interactions in highly active filler reinforced mixtures is not explicit and has not been investigated in depth. For this purpose, the influence of treated distillate aromatic extract (TDAE) oil content and its addition time on interactions between silica and rubber chains were investigated in this study. Rubber–filler and filler–filler interactions of uncured and cured silica-filled SBR/BR blends were characterized by using rubber layer L concept and dynamic mechanical analysis, whereas mechanical properties were studied by tensile test and Shore A hardness. Five parts per hundred rubber (phr) TDAE addition at 0, 1.5, and 3 min of mixing were characterized to investigate the influence of TDAE addition time on rubber–filler interactions. It was observed that addition time of TDAE can influence the development of bounded rubber structure and the interfacial interactions, especially at short time of mixing, less than 5 min. Oil addition with silica at 1.5 min of mixing resulted in fast rubber layer development and a small reduction in storage shear modulus of uncured blends. The influence of oil content on rubber–filler and filler–filler interactions were investigated for the binary blends without oil, with 5 and 20 phr TDAE content. The addition of 5 phr oil resulted in a slight increase in rubber layer and 0.05 MPa reduction in Payne effect of uncured blends. The storage tensile modulus of vulcanizates at small strains decreased from 13.97 to 8.28 MPa after oil addition. Twenty parts per hundred rubber (phr) oil addition to binary blends caused rubber layer L to decrease from 0.45 to 0.42. The storage tensile modulus of the vulcanizates and its reduction with higher amplitudes were incontrovertibly high among the vulcanizates with lower oil content, which were 13.57 and 4.49 MPa, respectively. When any consequential change in mechanical properties of styrene–butadiene rubber (SBR)/butadiene rubber (BR) blends could not be observed at different TDAE addition time, increasing amount of oil in blends enhanced elongation at break, and decreased Shore A hardness and tensile strength.

Download Full-text

Relationship between the Stereocomplex Crystallization Behavior and Mechanical Properties of PLLA/PDLA Blends

Polymers ◽

10.3390/polym13111851 ◽

2021 ◽

Vol 13 (11) ◽

pp. 1851

Author(s):

Hye-Seon Park ◽

Chang-Kook Hong

Keyword(s):

Mechanical Properties ◽

Lactic Acid ◽

Crystallization Behavior ◽

Mechanical Analysis ◽

X Ray Diffraction ◽

Nucleation Agent ◽

Scanning Calorimetry ◽

Nucleation Sites ◽

Wide Range ◽

Degree Of Crystallization

Poly (l-lactic acid) (PLLA) is a promising biomedical polymer material with a wide range of applications. The diverse enantiomeric forms of PLLA provide great opportunities for thermal and mechanical enhancement through stereocomplex formation. The addition of poly (d-lactic acid) (PDLA) as a nucleation agent and the formation of stereocomplex crystallization (SC) have been proven to be an effective method to improve the crystallization and mechanical properties of the PLLA. In this study, PLLA was blended with different amounts of PDLA through a melt blending process and their properties were calculated. The effect of the PDLA on the crystallization behavior, thermal, and mechanical properties of PLLA were investigated systematically by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD), polarized optical microscopy (POM), dynamic mechanical analysis (DMA), and tensile test. Based on our findings, SC formed easily when PDLA content was increased, and acts as nucleation sites. Both SC and homo crystals (HC) were observed in the PLLA/PDLA blends. As the content of PDLA increased, the degree of crystallization increased, and the mechanical strength also increased.

Download Full-text

Modeling and experimental study on the mechanical behavior of glass/basalt fiber metal laminates after thermal cycling

International Journal of Damage Mechanics ◽

10.1177/1056789521998731 ◽

2021 ◽

pp. 105678952199873

Author(s):

Mehdi Abdollahi Azghan ◽

F Bahari-Sambran ◽

Reza Eslami-Farsani

Keyword(s):

Thermal Cycling ◽

Glass Fibers ◽

Basalt Fiber ◽

Tensile Modulus ◽

Alloy Sheet ◽

Experimental Results ◽

Weibull Function ◽

Basalt Fibers ◽

Thermal Stabilities ◽

Fiber Metal

In the present study, the effect of thermal cycling and stacking sequence on the tensile behavior of fiber metal laminate (FML) composites containing glass and basalt fibers was investigated. To fabricate the FML samples, fibers reinforced epoxy composite were sandwiched between two layers of 2024-T3 aluminum alloy sheet. 55 thermal cycles were implemented at a temperature range of 25–115°C for 6 min. The tensile tests were carried out after the thermal cycling procedure, and the results were compared with non-thermal cycling specimens. Scanning electron microscopy (SEM) was employed for the characterization of the damage mechanisms. The FMLs containing four basalt fibers’ layers showed higher values of tensile strength, modulus, and energy absorption. On the other hand, the lowest strength and fracture energy were found in the asymmetrically stacked sample containing basalt and glass fibers, due to weak adhesion between composite components (basalt and glass fibers). The lowest tensile modulus was found in the sample containing glass fibers that was due to the low modulus of the glass fibers compared to basalt fibers. In the case of the samples exposed to thermal cycling, the highest and the lowest thermal stabilities were observed in basalt fibers samples and asymmetrically stacked samples, respectively. In accordance with the experimental results, a non-linear damage model using the Weibull function and tensile modulus was employed to predict the stress-strain relationship. The simulated strain–strain curves presented an appropriate agreement with the experimental results.

Download Full-text