Q1) Explain the Thermoplastic and Thermosetting plastic?

A1)

Like thermoplastic elastomers like styrene-isoprene-styrene block copolymers, it can be used as an adhesive. Polymers provide strength, flexibility, and the capacity to spread and interact on an adherend surface—all of which are necessary for appropriate adhesion levels to form.

At normal temperatures, thermoplastics provide strong, long-lasting adhesion, and they can be softened for application without degrading. Nitrocellulose, polyvinyl acetate, vinyl acetate-ethylene copolymer, polyethylene, polypropylene, polyamides, polyesters, acrylics, and cyanoacrylics are some of the thermoplastic resins used in adhesives.

Thermoplastics and thermosets are the two main types of thermoplastics. At normal temperatures, thermoplastics provide strong, long-lasting adhesion, and they can be softened for application without degrading. Nitrocellulose, polyvinyl acetate, vinyl acetate-ethylene copolymer, polyethylene, polypropylene, polyamides, polyesters, acrylics, and cyanoacrylics are some of the thermoplastic resins used in adhesives.

Q2) Explain the RESIN TRANSFER MOULDING (RTM)?

A2)

Resin Transfer Moulding (RTM) allows the moulding of components with complex shapes and large surface areas with a good surface finish on both sides. It's a process that works well for short and medium production runs, and it's used in a variety of transportation applications (truck cabs are an example).

The Mould is placed in the pressure machine, which is in charge of applying pressure to the resin container in order to force the resin into the moulding region.

• Basfiber Fabrics are positioned over the mould in the thicknesses and layers required to obtain the expected properties of the final product.

• In the mould, heat and pressure are applied to force the resin to cover all of the space between the fabric layers, ensuring resin impregnation.

• After acquiring the mould form, the finished product is cured and taken from the mould for the finishing stage.

• The product is polished and varnished for a brighter outcome, and the edges are cut.

• The product can be painted in a variety of colours, allowing things to be made on a production line.

When it comes to closed moulding for composite manufacture, there are a variety of solutions. Compression moulding produces low-cost parts for high-volume production, but it demands a large capital investment in presses, equipment, and tooling.

Q3) Explain the Hand lay-up method?

A3)

Hand lay-up moulding is the process of laying down reinforcement textiles and layering on the matrix resin until the appropriate thickness is achieved. This is the most time-consuming and labor-intensive composite processing technology, yet it is used in conjunction with the autoclave method to produce the majority of aerospace composite products. Long fibers can be aligned with controlled orientational quality thanks to the hand assembly involved in the lay-up technique. This approach also has the advantage of being able to accommodate irregularly shaped goods. Low-performance composites, such as fiber-glass boats and bath tubs, take advantage of these advantages. The earliest and most basic method for making reinforced plastic laminates is hand lay-up. The hand lay-up processes require a small amount of capital. A spray gun for applying resin and gel coat is usually the most expensive piece of equipment. Some fabricators pour or brush the resin into the moulds, eliminating the need for a spray gun. The size of the part that can be created is almost limitless. Wood, sheet metal, plaster, and FRP composites can all be used to make moulds.

• Typically used to manufacture polyester or epoxy resin parts such as boat hulls, tanks and vessels, and pick-up truck canopies • The procedure is relatively straightforward; the resin and reinforcement are applied against the surface of an object.

• open (one-sided) mould and leave to cure, or spray-up the resin/reinforcement onto the mould with a spray gun.

• To improve surface quality and protect the composite from the outdoors, a gel coat is frequently put to the mould before to use.

• A gel coat is a thin layer of resin that is typically seen on the exterior surface of smaller boats. It is usually 0.4 to 0.7 mm thick

Q4) Explain the process of spray-up moulding?

A4)

Using a spray gun and a fiber cutter, spray-up moulding is substantially less labour demanding than manual lay-up moulding. Only short fiber reinforced composites, however, can be manufactured. • A continuous fiber is fed into the cutter and chopped, then sprayed onto a mould with a stream of resin mist and catalyst given via separate nozzles.

• The sprayed fiber and resin combination cures quickly at room temperature on the mould, and the product is created.

• Large and complex-shaped things can be easily manufactured thanks to the spraying process.

Q5) What is filament winding?

A5)

Filament winding produces hollow structures that are extremely strong. The filament winding process produces an optimized product that is ideal for pressure vessels, aerospace components, golf clubs, military armaments, and hundreds of other applications by cross-weaving continuous rovings of carbon fiber, fiberglass, or aramid fiber and embedding them in a resin matrix. This is the production procedure of choice anywhere strength at a low weight is required, as well as durability and certain performance qualities.

Q6) Explain the three decades of filament winding?

A6)

With our precision filament winding method, Advanced Composites Inc. Has been producing high-grade composite tubing, aircraft structures, and other specialty products for almost two decades. With a variety of filament winding machines and the ability to create, prototype, and build at nearly any scale, ACI has established itself as a dependable production partner for any company that requires filament-wound structures. There are two main components to the filament winding process. A carriage arm travels horizontally up and down the length of the mandrel while a stationary steel mandrel rotates. A winding eye on the travelling arm collects and distributes the rovings, which are commonly made of carbon, fiberglass, or a combination of the two. The rovings wrap around the mandrel as it rotates, forming a composite layer on the mandrel's surface. The rate of motion of the carriage and the rotating speed of the mandrel, both of which are automated, define the precise alignment of the composite matrix. The fibers are impregnated in a resin before they come into contact with the mandrel, and the resin solidifies with the fiber to form the final composite material.

Q7) Explain the concept of Injection moulding?

A7)

Injection moulding (also known as injection moulding in the United States) is a manufacturing method that involves injecting molten material into a mould. Injection moulding can be done with a variety of materials, including metals (for which die-casting is used), glassware, elastomers, confections, and, most typically, thermoplastic and thermosetting polymers. The part's material is supplied into a heated barrel, mixed (using a helical screw), and then injected into a mould cavity, where it cools and hardens to the cavity's configuration. [1]:240 Molds are manufactured by a mould-maker (or toolmaker) from metal, usually steel or aluminium, and precision-machined to produce the features of the required part after a product is created, usually by an industrial designer or an engineer. Injection moulding is commonly utilized to produce a wide range of parts, from small components to whole automotive body panels. Some basic injection moulds can be made using advances in 3D printing technology, which use photopolymers that do not melt during the injection moulding of some lower-temperature thermoplastics.

Injection moulding is done with a unique equipment that consists of three parts: an injection unit, a mould, and a clamp. To make the injection moulding process easier, parts must be properly developed; the material used for the part, the intended shape and features of the part, the material of the mould, and the properties of the moulding machine must all be considered.

Q8) What are the Applications of fiber –reinforced epoxies?

A8)

Kevlar, Nomex, and Technora are the most well-known aramid fibers. Aramids are made by reacting an amine group with a carboxylic acid halide group (aramid); this usually happens when an aromatic polyamide is spun into a crystalline fiber from a liquid solution of sulfuric acid. After that, the fibers are spun into larger threads, which are subsequently woven into big ropes or woven fabrics (Aramid). Aramid fibers come in a variety of grades based on their strength and rigidity, allowing the material to be adjusted to specific design requirements, such as cutting the tough material during manufacturing.

Q9) Explain the Recycling of Polymer Matrix Composites?

A9)

The resin system is chosen depending on the product's functional and economical requirements. Although a variety of reinforcing fibers are employed in composites, the PRGF contributes more than 90% of the total amount of produced polymer matrix composites. PRGF composites have a high degree of adaptability and can be used in a wide range of applications. It has a wide range of applications, from roof tiles to vehicle parts. However, from an ecological standpoint, it is problematic. The thermoset matrix composites sector in Brazil is estimated to generate 10,000 tonnes of solid waste per year, which is typically disposed of in sanitary and industrial embankments [2]. Figure 1 shows that the amount recycled is less than 1% of the total created, excluding post-consumed items. The solid residues formed during the manufacturing of PRGF goods, as well as the post consumed products, must be properly managed (collection, packaging, transport, treatment, and/or final disposition). This is done in order to minimize environmental damage while simultaneously protecting people's health and wellbeing. While the usage of thermoplastics for packing results in hundreds of tonnes of solid waste each year, the thermoset polymer composite material creates only a fraction of that. The non-melting resin utilized as a matrix, however, is an aggravating problem. It is also necessary to evaluate the projected expansion of this material's use in the Brazilian market. The entry of foreign resin-producing industries corroborates this.

Q10) What is hydrogenation and cracking?

A10)

The material is treated in a hydrogen environment at temperatures ranging from 300 to 500 degrees Celsius and pressures ranging from 100 to 400 bar, yielding 65-90 percent oil (syncrude), 10-20 percent gases, and up to 20% solid residues.

To create oligomeric waxy liquids suitable for further catalytic cracking, the material is heated to 400°C to 600°C and at pressures slightly over atmospheric. The gases that are produced are used to power the operation.

Q11) Explain the glass separation method?

A11)

The composite scrap must first be reduced to a size and shape that permits for efficient transportation and handling. The shopped material is then processed. The polymer breaks down and burns when composite materials are treated in a fluidized bed at high temperatures. This causes fibers and any filler in the fluidized bed to be transported out into the gas stream. A cyclone, for example, can remove the fibers and fillers from the gas stream. The recovered fiber has some recycling value, but it is lower than virgin fibers for several reasons: the fiber length is no longer uniform or of the same size; the glass will no longer wet out as quickly as virgin fiber glass; the glass has filler and resin attached, reducing the weight of fiber per weight used; and the recovered fibers have about half the strength of virgin glass fibers.