The impact of natural fibers’ characteristics on mechanical properties of the cement composites

Mechanical and durability properties of natural fiber-reinforced geopolymers containing lead smelter slag and waste glass sand

Introduction : Acrylic denture in its use often results in fractures and one of the causes is due to poor mechanical resistance, especially to impact strength. Several methods to prevent broken acrylic, include the addition of fibers that function as reinforcement. There are 2 types of fibers, synthetic and natural fibers. Synthetic fibers are relatively expensive, so an alternative is needed, namely the use of natural fibers (Ramie and banana stem). This study purposed to determine the effect of adding ramie fiber and banana stem to impact and flexural strength of acrylic denture base. Methods : Experimental Laboratory, number of 60 samples consisted of 30 samples for flexural and impact tests. The sample was an acrylic plate; size 65x10x2.5 mm for Flexural Test and 80x10x4 mm (Flatwise impact method without notched) for Impact Test. The fiber concentration added was 1.6% of the sample weight. The sample consisted of 3 groups, namely control, the addition of ramie and banana stem fibers. Flexural test with UTM and Impact test with Charpy method. Results : Flexural and impact strength mean value of the ramie fiber group had the highest value (132.7459MPa; 7.9859 x 10-3Joule/mm2), followed by the control group (99.8499MPa; 4.2757 x 10-3Joule/mm2) and smallest value was in banana midrib fiber group (91.6865MPa; 3.0303 x 10-3Joule/mm2). The LSD test of significance(p) between each group in flexural and Impact Strength tests showed a significant difference (p<0.05). Pearson correlation test showed a significant positive correlation between the two tests. Conclusion : The addition of ramie fiber can increase the impact and flexural strength of denture acrylic, but it is different from the addition of banana midrib fiber because the presence of flavonoids (phenol compounds) it contains causes a decrease in the strength of denture acrylic.

Effect of micro-sized silica aerogel on the properties of lightweight cement composite

The influence of pre-coated EGA and aerogel on the properties of lightweight self-compacting cementitious composites

Natural fibers are widely use to replace the synthetic fibers in polymer composites due to their inherent properties. In the present study, Thermogravimetric analysis (TGA) of sisal, jute and ramie fiber was done before and after chemical treatment. This study includes the effect of chemical treatment on the thermal stability of sisal, jute and ramie fibers. The degradation of fibersand the phases of degradation were studied with increase in temperature. Results showed that chemical treatment improved the thermal stability of ramie and sisal fiber while jute fiber showed not much change in properties by chemical treatment.

In recent years, natural fibers reinforced composites have received much attention because of their lightweight, nonabrasive, combustible, nontoxic, low cost and biodegradable properties. Among the various natural fibers; flax, bamboo, sisal, hemp, ramie, jute, and wood fibers are of particular interest. A lot of research work has been performed all over the world on the use of natural fibers as a reinforcing material for the preparation of various types of composites. However, lack of good interfacial adhesion, low melting point, and poor resistance towards moisture make the use of natural fiber reinforced composites less attractive. Pretreatments of the natural fiber can clean the fiber surface, chemically modify the surface, stop the moisture absorption process, and increase the surface roughness. Among the various pretreatment techniques, graft copolymerization and plasma treatment are the best methods for surface modification of natural fibers. Graft copolymers of natural fibers with vinyl monomers provide better adhesion between matrix and fiber. In the present article, the use of pretreated natural fibers in polymer matrix‐based composites has been reviewed. Effect of surface modification of natural fibers on the properties of fibers and fiber reinforced polymer composites has also been discussed. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers

In this study, the compression molding technique was used to fabricate hybrid composites using different wt.% of the glass and ramie fibers in different stacking sequences. The physical (density, water absorption, and wear resistance) and mechanical (tensile strength, hardness, and impact strength) and morphology studies were performed for the glass and ramie fibers and the effect of stacking sequencing was studied. A technique for order of preference by similarity to the ideal solution model was used to determine the optimal reinforcement composition in the hybrid composites. The stacking sequence played a crucial role in the physical and mechanical characteristics of the hybrid composites. The GRG (stacking sequence: Glass (4 wt.%)-Ramie (4 wt.%)-Glass(4 wt.%)) hybrid composite showed optimal characteristics; tensile strength: 114 MPa, hardness: 41 HV, impact energy: 3.5 J m−1, void content: 1.09% and wear: 63 μm. However, if glass fibers were sandwiched between the ramie fiber layer, the composite showed lower physical and mechanical characteristics; tensile strength: 72 MPa, hardness: 28 HV, impact energy: 3 J m−1. The glass fiber reinforced composites (GG and GGG) exhibited better water absorption characteristics. The RRR composite’s impact strength was comparable with the GGG composites due to the stacking of the composites. Moreover, the glass fiber composites stacking (RR to RGR) exhibited lower tensile strength than ramie fiber composites stacking (GG to GRG). The microstructural analysis of the fractured composite surface revealed voids, de-lamination, interfacial bonding of the fibers with the matrix, fiber pull-out, and matrix distribution.

Agroforestry system is a form of integrated land use involving forestry and agriculture, which is expected to help overcome the problems of increasing demand for agricultural land, decreasing environmental quality and poverty rates, and resulting in increasingly complex global issues. This system includes a combination of forestry crops with agricultural crops or other plants that can grow together on the same land. The application of agroforestry can improve agricultural welfare, overcome the environmental crisis and poverty, and maintain the sustainability of natural resource conservation. Ramie (Boehmeria nivea) fiber is an interesting plant to cultivate using an agroforestry system. It is easy to cultivate, positively impacts the environment, and has many application benefits because it is known as a strong and long-lasting fiber. On the other hand, the textile industry in Indonesia still predominantly uses cotton fiber which has low productivity, so the value of cotton imports increases yearly. Given the increasing demand for environmentally friendly and sustainable textiles, researchers and industry stakeholders are looking for other materials that provide functionality and environmental advantages. Ramie fiber is a type of natural fiber with advantages compared to other natural fibers, such as tensile strength, mechanics, and cellulose content, which has similar characteristics to cotton so that ramie can be applied as a functional textile material to replace cotton. This review paper aims to provide an in-depth overview of all ramie fiber properties, methods, and applications for functional textiles. This article highlights the environmental benefits of ramie fiber and its potential to encourage a more sustainable textile industry, citing various sources. Keywords: agroforestry, forestry crops, functional textile, ramie fiber, ramie’s properties

BackgroundVarious recent studies have investigated the use of traditional fibers (metallic or synthetic) as reinforcement in mortar. In recent times, there has been growing interest in using natural fibers as reinforcement in cement composites. This study was conducted to assess the impact of date palm, doum palm, and sisal fibers on the mechanical properties of cement composites. Genetic modeling was chosen to find the shear damage at the fiber-matrix interface of the three cement composites using genetic crossing operator, which allows us to calculate the damage at the interface using two damages of the matrix and the fibers, respectively.ResultsOur objective is to examine and evaluate the interface damage of date palm/mortar, doum palm/mortar and sisal/mortar under different mechanical tensile stresses ranging from 25 to 37 MPa with fiber volume fraction from 1 to 5%. It was found that the interface damage of date palm/mortar and doum palm/mortar cement composites was minimal compared to that of sisal/mortar. However, several researchers found that an increase in fiber volume fraction leads to decrease in mechanical properties and density in cement composites what we confirmed in this study that interface damage increases when the volume fraction increases.ConclusionsThe results are in line with the findings of a recent experimental study on the use of other plant fibers. Their results showed that incorporating ramie fibers resulted in a 27% increase in compressive strength, whereas the use of synthetic fibers resulted in 4% decrease in tensile strength in compression. It is recommended the use of doum and date palm natural fibers in the composition of mortars with a fiber volume fraction of 1 to 5% in order to reduce and avoid interface damage and limit the negative impact of synthetic fibers on the environment.

Natural fiber composite is the most preferable research area in the modern situation due to its availability, applications, and ecofriendly quality. This paper deals with the influence of hemp fiber with the various compositions of the ramie fiber and some basic mechanical properties of banana fiber composites. The hemp fiber is maintained as 20 percentage of total volume. Then, the remaining volume percentage is shared with the ramie fiber and banana fiber with various combinations. Eleven specimens were prepared to identify the some basic mechanical properties. The chemical compositions were mentioned as a pie chart, and then experimental results were plotted as graphical representations like line diagram and radar diagram for clear identification that the composite with higher ramie fiber concentration provided the greater results in the mechanical behaviors. The suitable composite combinations were recommended based on their superior properties as conclusions.

The mechanical properties of cementitious composites before and after exposure to high temperature are affected by calcium–silicate–hydrate (C–S–H) gels. To evaluate the effects of high temperature, plyvinyl alcohol (PVA) fiber content, and the cooling method on properties of cementitious composites, physical, mechanical, and microscopic tests were performed in this study. The target temperatures were 25, 100, 200, 300, 400, 600, and 800 °C. The PVA fiber contents were 0.0, 0.3, 0.6, 0.9, 1.2, and 1.5 vol%. The high-temperature resistance of PVA fiber-reinforced cementitious composite (PVA-FRCC) specimens was investigated through changes in their appearance, mass loss, compressive strength, splitting tensile strength, flexural strength, and microstructure. The results showed that PVA fibers reduced the probability of explosion spalling in the PVA-FRCC specimens exposed to high temperatures. The mass loss rate of samples exposed to temperatures below 200 °C was small and lower than 5%, whereas a significant mass loss was observed at 200 °C to 800 °C. A small rise in the cubic compressive and splitting tensile strengths of samples was found at 400 °C and 300 °C, respectively. Below 400 °C, the fibers were beneficial to the mechanical strength of the PVA-FRCC specimens. Nevertheless, when the temperature was heated above 400 °C, melted fibers created many pores and channels, which caused a decrease in the strength of the specimens. The method of cooling with water could aggravate the damage to the cementitious composites exposed to temperatures above 200 °C. High temperature could lead to the decomposition of the C–S–H gels of the PVA-FRCC samples, which makes C–S–H gels lose their bonding ability. From the perspective of the microstructure, the structure of PVA-FRCC samples exposed to 600 °C and 800 °C became loose and the number of microcracks increased, which confirmed the reduction in macro-mechanical properties.

Fiber-reinforced composites are among the recognized competing materials in various engineering applications. Ramie and pineapple leaf fibers are fascinating natural fibers due to their remarkable material properties. This research study aims to unveil the viability of hybridizing two kinds of lignocellulosic plant fiber fabrics in polymer composites. In this work, the hybrid composites were prepared with the aid of the hot compression technique. The mechanical, water-absorbing, and thickness swelling properties of ramie and pineapple leaf fiber fabric-reinforced polypropylene hybrid composites were identified. A comparison was made between non-hybrid and hybrid composites to demonstrate the hybridization effect. According to the findings, hybrid composites, particularly those containing ramie fiber as a skin layer, showed a prominent increase in mechanical strength. In comparison with non-hybrid pineapple leaf fabric-reinforced composites, the tensile, flexural, and Charpy impact strengths were enhanced by 52.10%, 18.78%, and 166.60%, respectively, when the outermost pineapple leaf fiber layers were superseded with ramie fabric. However, increasing the pineapple leaf fiber content reduced the water absorption and thickness swelling of the hybrid composites. Undeniably, these findings highlight the potential of hybrid composites to reach a balance in mechanical properties and water absorption while possessing eco-friendly characteristics.

In the current scenario, components demand superior mechanical, thermal, and tribological properties that can be achieved with the use of synthetic fibers. However, the environmental and energy issues are the problem associated with the synthetic fiber composites. Because of this, natural fiber-reinforced polymers (NFRPs) composites become the eye candies of the researchers. Renewability, sustainability, availability, and lower cost are the leading qualities that take them to the apex of the polymer industries. Researchers are searching the applications based on supreme qualities of natural fibers in several fields such as automobile, space, homeware, textiles, etc. They hold good properties as well as have some limitation toward strength, water absorption, and flammability because of the chemical constituents present in the plant fibers. Therefore, in order to take the advantage of both types of fibers, researchers use hybrid composites. This hybridization brings out various attractive properties of both natural and synthetic fiber results in attractive properties at economical cost of the finished product. Therefore, the present discussion is a review on the physical and mechanical properties of the hybrid fiber-based polymer composites reinforced with synthetic and natural fibers.

The distinct terahertz spectra of ramie and bamboo fibers were obtained by means of terahertz time-domain spectroscopy. Numerical simulation for glucose based on density functional theory has been performed to interpret the observed THz features theoretically. The results indicate that the intramolecular motions do make partial contribution to experimental features of cellulosic fibers, but most of the features are attributed to intermolecular modes. The investigation suggests that THz spectroscopy is a promising candidate for distinguishing bamboo and ramie fibers, and this will open new prospect to identify textile fibers especially those with similar chemical composition.

Low-Voltage SEM of Natural Plant Fibers: Microstructure Properties (Surface and Cross-Section) and their Link to the Tensile Properties