PENGARUH PENAMBAHAN SERAT IJUK PADA PAVING BLOCK BERBAHAN PLASTIK HDPE

The waste problem continues to be a complex issue. On the one hand, the use of plastic still cannot be abandoned by humans, but on the other hand the waste produced is very difficult to decompose. In Indonesia, in 2015 the amount of waste reached 64 million tons / year. Palm fiber is one of the materials that can be used as composite fiber. In this study, a research will be conducted on the manufacture of paving blocks made from HDPE plastic combined with variations of 0%, 1%, 2% and 3% palm fiber. Plastic waste is melted and put into a mold and then combined with palm fiber. From the test results, the highest compressive strength (2% fiber variation) was 45.91 kg/cm2 and the average compressive strength was 45.28 kg/cm2. This compressive strength is under the minimum compressive strength standard of SNI Permasalahan sampah masih terus menjadi isu kompleks. Di satu sisi, penggunaan plastik masih belum bisa ditinggalkan manusia, namun di sisi lain sampah yang dihasilkan sangat sulit terurai. Di indonesia, pada tahun 2015 tercatat banyaknya sampah mencapai 64 juta ton/tahun. Ijuk merupakan salah satu material yang dapat digunakan sebagai serat komposit. Pda penelitian ini akan dilakukan penelitian mengenai pembuatan paving block berbahan dasar plastik HDPE yang dikombinasikan dengan variasi serat ijuk 0%, 1%, 2 % dan 3%. Limbah plastik dilelehkan dan dimasukkan ke dalam cetakan lalu dipadukan dengan serat ijuk. Dari hasil pengujian, didapatkan kuat tekan tertinggi (variasi serat 2%) sebesar 45,91 kg/cm2 dan kuat tekan rata-ratanya sebesar 45,28 kg/cm2. Kuat tekan ini berada di bawah standar kuat tekan minimal dari SNI.

Safety Risks of Plant Fiber/Plastic Composites (PPCs) Intended for Food Contact: A Review of Potential Hazards and Risk Management Measures

Plant fiber/plastic composites (PPCs), with the benefits of low cost and easy processing, have been widely used in the production of various food contact products. They are generally considered to be economical and environmentally friendly because of their natural raw materials (plant fibers) and recommended to be one of the ideal alternatives to traditional petrochemical-based plastics. However, in addition to plastic resins and plant fibers, some indispensable additives are involved in the production process of PPCs, which may pose food safety risks. To date, excessive migration of hazardous substances (such as melamine) has been reported in some products made of PPCs, and the safety and applicability of PPCs as food contact materials need to be further studied. In this paper, the main raw materials of PPCs used for food contact are taken as the pointcut to analyze the possible hazards, sources of hazards, and existing risk management measures in various countries. The conclusion shows that PPCs used for food contact may have potential safety risks at present. However, systematic research on migration methods and safety assessment are still insufficient, and further studies are needed regarding the main safety risks and migration patterns.

Three Stages of Composite Specimen Destruction in Static Failure

The paper presents the results of standard specimen fracture made of anisotropic carbon fiber plastic with an epoxy matrix. Static stepwise loading of the specimen was carried out on an Instron 8801 testing machine to determine the characteristics of ductile fracture G1C in the first mode in accordance with ASTM D5528. During loading, the parameters of acoustic emission (AE) signals, such as AE impulse amplitudes and their energy were synchronously recorded. At the same time, the magnitude of the opening and the growth of the crack initiated by the artificial cut at the end of the specimen were recorded. According to the analysis of the acoustic emission signals, three zones with different G1C behaviour were identified: initial crack propagation, its stationary growth and accelerated fracture of the specimen. The zonal character of the change in the acoustic emission signals made it possible to determine the energy of the acoustic emission signals as diagnostic evidence for the onset of rapid destruction of the specimen. The amplitude of the AE-signals in the zones, however, remained constant. Online monitoring of changes in the energy of acoustic emission signals will prevent the onset of rapid destruction of an object in places of its deformations. The paper does not aim at defining G1C as usual. It presents the investigation of the fracture stages for a composite material using an acoustic emission method.

Combining Fiber Enzymatic Pretreatments and Coupling Agents to Improve Physical and Mechanical Properties of Hemp Hurd/Wood/Polypropylene Composite

Natural fiber/plastic composites combine the low density and excellent mechanical properties of the natural fiber with the flexibility and moisture resistance of the plastic to create materials tailored to specific applications in theory. Wood/plastic composites (WPC) are the most common products, but many other fibers are being explored for this purpose. Among the more common is hemp hurd. Natural fibers are hydrophilic materials and plastics are hydrophobic, therefore one problem with all of these products is the limited ability of the fiber to interact with the plastic to create a true composite. Thus, compatibilizers are often added to enhance interactions, but fiber pretreatments may also help improve compatibility. The effects of pectinase or cellulase pretreatment of wood/hemp fiber mixtures in combination with coupling agents were evaluated in polypropylene panels. Pretreatments with pectinase or cellulase were associated with reduced thickness swell (TS24h) as well as increased modulus of rupture and modulus of elasticity. Incorporation of 5.0% silane or 2.5% silane/2.5% titanate as a coupling agent further improved pectinase-treated panel properties, but was associated with diminished properties in cellulase treated fibers. Combinations of enzymatic pretreatment and coupling agents enhanced fiber/plastic interactions and improved flexural properties, but the effects varied with the enzyme or coupling agent employed. The results illustrate the potential for enhancing fiber/plastic interactions to produce improved composites.

Influence of the structure and thermomechanical properties of oriented carbon plastics on their tribotechnical characteristics

It has been established that carbon plastics are increasingly used in various industries as structural materials. By the set of their properties, carbon plastics outperform steel, cast iron, alloys of non-ferrous metals. However, the application of these materials for parts of machine friction units is still limited due to the difficult operating conditions of modern tribosystems. This work aims to conduct a comprehensive experimental study of the tribological properties of materials in the tribosystem "carbon plastic-metal" taking into consideration their structure, as well as the mechanical-thermal characteristics. Comparative tests of the dependence of the friction coefficient on load for metal and polymeric anti-friction materials have shown a decrease in the friction coefficient for plastics by 3...4 times (textolite, carbotextolite, and carbon-fiber plastics). The influence of the filler orientation relative to the slip plane on the anti-friction properties of carbon-fiber plastics was investigated; it was found that the direction of fiber reinforcement in parallel to the friction area ensures less carbon-fiber plastic wear. A linear dependence of the wear intensity of carbon-fiber plastics, reinforced with graphite fibers, on the heat capacity and energy intensity of the mated steel surface has been established. Based on the microstructural analysis, a layered mechanism of the surface destruction of carbon-fiber plastics was established caused by the rupture of bonds between the fiber parts, taking into consideration the direction of the fibers' location to the friction surface. The results reported here could provide practical recommendations in order to select the composition and structure of materials for the tribosystem "carbon-fiber plastic-metal" to be used in machine friction units based on the criterion of improved wear resistance

Application of processing fiber-plastic composite washing

Introduction. Innovative, new materials are increasingly used in transport construction, among which composite materials are becoming widespread.Small bridges and elements of large bridges, such as roadway slabs, pavements, railings, composite reinforcement, reinforcement elements, are made of composite materials.Recently, the use of polymer composite materials for the manufacture of lightly loaded structural elements of transport structures, such as lighting poles, drainage trays, railings.Much attention should be paid to the fiberglass composite railing, which has a number of advantages over traditional metal fencing. Unfortunately, at present there are no clearly defined in Ukraine regulations on fiberglass composite fencing, so this topic is relevant and necessary for the transport industry.Problem Statement. From the literature analysis it is established that the railings of highways and sidewalks are in difficult operating conditions, are constantly exposed to aggressive environments - water, chemicals, salts.Goal. Increasing the durability of the railing by using new materials.Results. The analysis of production of a fiberglass profile is carried out. On the basis of the conducted researches the general requirements to a protection of fiberglass composite washing machine are established. On the basis of the current normative documents the classification of a protection on a place of installation, type of filling of a skeleton, a method of fastening of risers is developed. The paper presents the main parameters and dimensions of the fence. Material requirements are set. Methods of control of a protection with establishment of a technique of test of a protection on resistance to action of horizontal and vertical loadings are developed. Recommendations on installation and installation of a protection of fiberglass composite washing machine are offered.Conclusions. The research results were used in the development of technical conditions for the protection of fiberglass composite washing machine.Keywords: road, composite, bridge, fencing, profile, fiberglass, artificial construction

Persistence of Foodborne Pathogens on Farmers Market Fomites

The number of farmers markets registered by the U. S. Department of Agriculture (USDA) has seen a significant increase, jumping from 1,755 in 1994 to 8,771 in 2019. Microbial studies have found evidence that produce sold at farmers can yield higher microbial counts than their retail counterparts; however, no previous literature explored the efficacy of microbial (bacteria and virus) persistence on a variety of different farmers market fomites over a 2-month period. The objectives of the current study were to conduct observations to determine the most commonly used food contact surface fomites at farmers markets and to investigate the persistence of key foodborne pathogens ( Escherichia coli O157:H7, Listeria monocytogenes, Salmonella spp., Staphylococcus aureus, and MS2 bacteriophage) on these fomites. A repeated-measures analysis of variance was used to compare the persistence rates of foodborne pathogens on cardboard, plastic, tablecloth, molded pulp fiber, and wicker baskets used to store, transport, and display produce at farmers markets. In general, molded pulp fiber, plastic and wicker surface materials supported the persistence of foodborne pathogens the most, with S. aureus demonstrating the highest log concentrations over the longest period of time. Additionally, Salmonella and E. coli strains also persisted for a significant period of time (approximately 32-days) on all fomites with the exception of tablecloth. The results suggest that foodborne pathogens on these fomites pose a high-risk of cross-contamination particularly if the fomites cannot be washed, rinsed, and sanitized effectively (e.g. cardboard). The results highlight the need avoid using porous, single-use storage containers such as cardboard, molded pulp fiber and wicker containers for extended periods of time and suggest the use of easily cleanable materials such as plastic containers.