Glass/polypropylene, recycled

Table 3.26 Properties of increased glass content recycled reinforced polypropylene resin...

Table 3.27 Properties of recycled 30 wt% glass/polypropylene repeatedly molded...

Application of Polypropylene Fiber and Recycled Glass in Component of Cement-Based Composite... 

Though the overall impact result of the hemp/epoxy composite was lower than the impact of the glass/epoxy composite, the impact associated with the matrix was very high. There are two ways to reduce the impacts associated with the matrix one is using bio-based matrix, the other is using a recycled matrix. Many studies involve the use of bio-based epoxy resin in thermoset composites, while recycled polypropylene and recycled polyethylene have been studied in new thermoplastic formulations. 

The main RTPs are nylons and polypropylenes, both as granules for molding and as glass mat TPs (GMT). Other glass-reinforced TP, particularly PET, PBT, PC and PPS, are steadily increasing in use. The value of the compounds is relatively high, encouraging some effort to recycle them. The overall use of RTPs remains relatively small, while the applications are necessarily technical and may be difficult to separate from other materials. 

Plastic lumber is recycled plastics processed such as commingled plastic, polyethylene plastic, and polypropylene plastic. To improve their performances different developments have been used such as specialty additives (lubricants, deoxidizers, etc.). An example is by adding as low as 10 wt% of short glass fiber to these recycled plastics can double their strength. Other fibers used include hemp, flax, and sisal. They are principally extruded other processes are used such as injection and compression molding, to produce products competitive to wood lumber on land and in the water. Compression molding allows for a deep-molded grain and a much more dense board. The density also helps the product resist moisture absorption and improves weatherability. 

A. Shakeri, and A. Ghasemian, Water absorption and thickness swelhng behavior of polypropylene reinforced with hybrid recycled newspaper and glass fiber. Appl. Compos. Mater. 17,183-193 (2010). 

In addition, self-reinforced fiber composites are far superior to glass and carbon fiber materials with regard to their energy consumption during production and recycling because of the low melting point of polypropylenes. Table 22.2 shows the comparison. 

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