Waste Plastic disposal is a major environmental Issue and it is obvious that industry must endeavour to minimise wastes.Recovery and recycle are favourable options as they generate wealth.All types of plastics are suitable for recycling. Besides mechanical recycling, chemical recycling,gasification and liquefaction can be used . Fibre-reinforced polymeric waste can be treated by pyrolysis . It is equally clear, however, that no single method provides a universal answer and a sensible recycling policy will probably involve different approaches .

A.REUSE OF ACRYLIC SCRAP FROM SHEET MANUFACTURE FOR SHEET MANUFACTURE

Acrylic, also known as  poly methyl methacrylate (PMMA), is a clear, colorless transparent plastic with a higher softening point, better impact strength, and better weatherablility than polystyrene (PS). Acrylic is widely used in many application fields, such as transparency roof, automobile parts,  etc. The principal commercial processes for the production acrylic sheets are extrusion and casting . The manufacturing of transparent acrylic sheet is normally produced by cell casting process, which utilizes two flat glass plates separated by an elastomeric gasket. The flexible gasket permits filling of the cell with monomer or syrup,prevents leakage, and controls thickness of the acrylic sheet. In general, gasket is used only once and must be removed from finished product by cutting in order to make a require sheet size. Most of acrylic scrap, residual acrylic material stick around unusable gasket, generated during cutting step and comprises of approximately 10% of total final production, which becomes as an industrial waste plastic.

In order to conserve and reduce the quantity of acrylic waste from the production process, the concept of cleaner technology could be  applied to demonstrate the alternative way to reduce the processing cost of acrylic cast sheet and decrease an industrial waste by using acrylic scrap recycle within the acrylic cast sheet process.

Approximately  10% of acrylic scrap is generated during cutting step. Recycling of acrylic waste scrap within the production process is a technical option that can  reduce the generation of acrylic waste scrap.

The acrylic monomer solution viscosity increases with increasing the concentration of acrylic waste scrap. According to the industrial preparation of acrylic cast sheet, the appropriate viscosity of acrylic syrup before pouring into a casting cell is in the range of 500-3000 cp, therefore the appropriate concentration of acrylic monomer solution mixed with acrylic waste scrap should almost reach that of industrial standard viscosity value. The appropriate concentrations of acrylic waste scrap mixed within the acrylic monomer solution are in the range of 4% and 5%, which give the viscosity values in the range of 500-1611 cp.

In experimental studies the acrylic waste scrap did not affect the impact strength and hardness properties of the acrylic cast sheet product although the tensile strength property of the acrylic cast sheet product increased with increasing the amount of acrylic waste.

The acrylic waste scrap did not affect  the transparency property of the acrylic cast sheet.

Acrylic waste scrap affects the UV resistance property but did not affect the heat resistance property. However, the UV resistance property of the acrylic cast sheet product mixed with the acrylic waste scrap can be improved by the addition of UV stabilizer additive, which is usually added to the final product of acrylic cast sheet before sale to customer.

Environmental Impact Evaluation of the Acrylic Scrap Recycle

According to data available for Pan Asia Industrial Co., Ltd, Thailand,  16,000 kg of acrylic monomer isfed into a batch reactor and approximate 1,600 kg of acrylic waste scrap is generated during the productionprocess per day.  5% (800kg/day) of acrylic waste scrap was the maximum concentration that can be recycled as a part of raw material for produces acrylic cast sheet. By using the material balance analysis  and the material grouping for simplified product life cycle assessment, the environmental impact evaluation of the 5% of acrylic scrap recycle was calculated.   5% of acrylic waste scrap recyclable can reduce the costs of raw material (acrylic monomer), waste disposal, processing, and transportation, which are approximate 6-7% saving of the total cost. It can be concluded that the recycling of acrylic waste scrap within the acrylic production process generates a double outcomes to industry both in environmental and economical aspects. In environmental aspect, company can minimize the waste and pollutions.  Economical aspect, company can optimize resource use while increasing resource productivity. This ensures that more product/or services areobtained from less energy and raw material input.

B.ACRYLIC POWDER FROM SCRAP RECYCLE AS FILLER IN THE MANUFACTURE OF BATHROOM FIXTURES.

Composite plastic scrap (vacuum formed acrylic plastic with glass fibre reinforcement) has low density and thus has to be precrushed to save transportation and landfilling costs. Reprocessing of problematic plastic scrap (composite plastics) by using mechanical methods like milling by collision in disintegrators has been tried successfully.For the milling of composite plastic scrap, different disintegrator mills wereused [9]. for the size reduction of the acrylic plastic constituent and on the separation of the glass fibre constituent. Plastic powder with a particle size of about 1–2 mm can beproduced by two step milling and 95 mass % of the glass fibre content can be separated by final selective milling.

The total amount of separated GFP was 45 mass %.As a result, we can use 55 mass % of acrylic plastic from the composite plastic scrap. GFP can be reused in the production of polymeric concrete products as reinforcement.

Industrial PMMA scrap can be divided into two groups: pure acrylic plastic scrap forms about 20% and reinforced acrylic plastic scrap about 80% of the total amount. PMMA scrap without technological additives cannot be recycled and reextruded to produce new PMMA sheet material because of the amorphous structure of this thermoplastic material. Heating up an acrylic plastic material overglass transition temperature (100 °C) converts the plastic into a rubber-like state, which makes this material ideal for vacuum forming. Continued heating causes thermal degradation of the material instead of melting.

Acrylic powder has found application as  as a new fillermaterial in  the Solid Surface casting technology for producing  bathroom washbasins. Commonly, washbasins are made from a composite material consisting of a binder agen(unsaturated polyester resin), a filler material (dolomite powder),and a catalyst agent added to the resin to accelerate hardening. The mixing ratios of the binder agent and the filler material are 25/75 mass %. The traditional filler material, used in the casting technology, is a high-white dolomite filler, composed of CaMg(CO3)2 with a density of 2850 kg/m3 and particle sizes of coarse fractions 0.2–0.6 mm and 0.1–0.3 mm, and of the fine fraction less than 0.1 mm. Acrylic powder was used to substitute for the high white dolomite filler. The best flow characteristics of the mixture were obtained with 50 mass % of acrylic filler and 50 mass % of matrix, but the best surface quality and hardness after polishing was achieved with a mixture of 66 mass % of the acrylic filler and 34 mass % of the resin matrix.

Flow characteristics of the mixture 66/34 could be improved by using a lower viscosity matrix.Based on the results of tensile and hardness tests, two composite materials, 34/66 and 40/60 were selected for the abrasive resistance test. This test showed that the composite 40/60 had the best relative wear resistance properties ( 0.94), v e = which were closest to the reference material PMMA. Reprocessed plastics washbasins, produced from the new composite material, will increase the wear resistance of the working surface. At the same time, as compared to the dolomite filler, double reduction in weight can be achieved.

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