Composites all-polymer

Rubber-toughened polystyrene composites were obtained similarly by polymerising the dispersed phase of a styrene/SBS solution o/w HIPE [171], or a styrene/MMA/(SBS or butyl methacrylate) o/w HIPE [172], The latter materials were found to be tougher, however, all polymer composites had mechanical properties comparable to bulk materials. Other rubber composite materials have been prepared from PVC and poly(butyl methacrylate) (PBMA) [173], via three routes a) blending partially polymerised o/w HIPEs of vi-nylidene chloride (VDC) and BMA, followed by complete polymerisation b) employing a solution of PBMA in VDC as the dispersed phase, with subsequent polymerisation and c) blending partially polymerised VDC HIPE with BMA monomer, then polymerisation. All materials obtained possessed mixtures of both homopolymers plus some copolymer, and had better mechanical properties than the linear copolymers. The third method was found to produce the best material. 

In the present chapter, different uses of nanocomposites in structural composites are presented. They can be used in the polymer matrix as nano-reinforcements or in the interfadal region in conventional composites in order to mainly improve interlaminar strength, and hence to avoid delamination. They can also exist in the form of nanocomposite fibers as reinforcement in all-polymer composites or directly as self-reiifforced nanocomposites. 

Another type of structural polymeric composite material which has motivated a special interest in the last years is all-polymer composites. In these materials, the use of nanofillers has been considered not only to improve the more usual mechanical properties such as stiffness or strength, but also with the objective to enhance their interlayer peel strength. Nanofillers have been incorporated both in the reinforcement and/or in the matrix. 

Different uses of nanoreinforcements in structural composites were presented such as nanocomposite fibers, nano-enhancements in conventional composites, nano-enhancements in all-polymer composites and singlepolymer nanocomposites. 

The results of matrix modification from the incorporation of nanofillers in all-polymer composites are very promising as a means of improving interfacial properties and the subsequent increase of the materials processing window, but further work is also needed in this direction. 

Among other factors, influenced on the reinforcement, Lipatov marks form and size of filler particles, character of their distribution and aggregation and also a number of common physical-chemical causes, typical for all polymer composites [1]. 

The concept of MFCs offers a wide variety of potential applications via designing and manufacturing of new types of materials and articles. In the first place are the polymer-polymer (also called all-polymer) composites, where the reinforcing elements represent... 

The presence of reinforcanent in polymer (nano)composites (Thomas et al. 2011 Wen 2007) generally increases the value of E modulus due to restrictions of vibrations and short-range rotational motions (Bindu and Thomas 2013 Dufresne 2000 Liu et al. 2005 Musto 2006). Exceptions to this behavior exist, and one of them was reported on the EeS2/polyimide composite (Sava 2009). Incorporation of low quantities of pyrite microparticles restrains the possible physical interactions among polyimide chains, decreasing the rigidity of the composite relative to the pristine polyimide. Another situation was mentioned for an all-polymer composite obtained from a pair of incompatible polymers polysulfone (PSF) (the matrix polymer) and cross linked polydimethylsiloxane (PDMS) submicron particles (the disperse phase) (Racles et al. 2013). All-polymer composites contain polymer nanoparticles as the disperse phase in a polymer matrix and, from the point of view of properties, these are situated between polymer blends and polymer composites. The PDMS particles act like a plasticizer for the PSF matrix (E p p = 2 GPa, E psp/pp,Ms = 0.7 GPa). 

Racles Carmen, Cristea Mariana, Doroftei Florica, and Alexandru Mihaela. All-polymer composites from two incompatible polymers. Soft Mater. 11 no. 4 (2013) 421—429. 

Alternative routes, due to environmental awareness and increasing interest in sustainable material concepts, have led to the development of bio- and green composites for structural composite applications, the so-called all-polymer composites or self-reinforced polymer composites . These new materials promise to overcome the critical problem of fiber-matrix adhesion in biocomposites by using chemically similar or identical cellulose materials for both matrix and reinforcement and are designated as all-cellulose composites [39, 40]. 

Combinations of PP with PE have also been reported. Arnold et al. reported the creation of an all-polymer composite by using woven PP tape fabrics or short PP tapes shredded from waste fabrics as the reinforcement in a LDPE matrix [69]. Fibre volume fractions of up to 61 % were achieved by consolidating PP tape fabrics between LDPE films. Although the mechanical properties of the final composites were not competitive compared to some of the other composites described in this review, the concept of using waste fabrics to enhance the properties of low stiffness LDPE is attractive since the materials used would otherwise typically be disposed of via landfill. 

These types of microheterogeneity are inherent in all polymer systems, filled with particulate and fibrous fillers, in two-phase and multi-phase polymer systems (mixtures of polymers with discrete and continuous distribution of components), as well as in polymer glues, coatings, fiber-reinforced plastics, i.e., in all polymer composites. However, in polymers with mineral reinforcement, microheterogeneity appears as a result of interfacial phenomena only in the... 

All polymer composites absorb substantial amounts of moisture or water in humid environment as well as in water. The most important concern in indoor and outdoor applications of natural fiber-based biocomposites with polymer matrices is their sensitivity to water absorption, which can reduce considerably their mechanical, physical, and thermal properties and performances. The water absorption of biocomposites results in the debonding or gap in the natural fiber-polymer matrix interfacial region, leading to poor stress transfer efficiency from the matrix to the fiber and reduced mechanical and dimensional stabilities as well [158]. It has been known that the hemiceUulose component in cellulose-based natural fibers may be mainly responsible for water absorption because it is more susceptible to water molecules than the crystalline cellulose component. Also, poor interfacial adhesion... 

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