Properties Of Single Polymer Composites Research Articles

Is the use of correct terms and definitions important in creation of new materials?

and widely applied term is a case in composite community, where the thermodynamic term ‘phase’ is used instead of the term ‘component’. Obviously, the misuse of the term ‘phase’ is a remnant from the time when the colloid chemistry was formulated (second half of 19th century, i.e. long before the polymer science was defined). The confusion of this misuse can be easily demonstrated by poly(vinylidene fluoride) (PVDF) exhibiting five crystalline polymorphic modifications (phases!) and one amorphous phase but PVDF is still a one-component system. While this example does not have a direct effect on the creation of new materials, the next one, the definition of the relatively new type of polymer composites, the single polymer composites (SPCs), does. SPCs have also been called: one polymer composites (R. Porter), homocomposites, self-reinforced composites, one-phase composites, homogeneous composites, or all-polymer composites. The concept of SPCs has been formulated by R. Porter some 40 years ago (DOI: 10.1007/BF00554928) as attempt to solve the basic problem in polymer science and technology, namely, the low adhesion quality between matrix and reinforcement due to their different chemical composition. The approach is quite simple – the matrix and the reinforcement have to be of the same polymer, i.e. to be chemically identical. The idea attracted the attention of academia and industry during the last decade when patents were registered and products were commercialized; nanofibrillar SPCs with superior mechanical properties were also created (DOI: 10.1002/mame.201200226). What is more, similar products were prepared and called also SPCs (DOIs: 10.1007/s10853-009-3792-1, and 10.1016/j.compscitech.2013.12.006) using highly oriented poly propylene (PP) (as reinforcement) and the random copolymer of PP (usually with polyethylene) as a matrix thus neglecting the basic requirement (R. Porter) for identical chemical composition of matrix and reinforcement. Strictly speaking, such composites belong to the category of polymer–polymer composites. The same holds for thermoplastic copolyesters reinforced with ‘homo’-poly(ethylene terephthalate). The argument that the two chemically different components belong to the same polymer family (DOI: 10.1016/j.compscitech.2013.12.006) could hardly be seriously considered – it only smears the boundary between the two types of composites, the polymer-polymer ones and the SPCs and makes the clear definition of single polymer composites hardly possible affecting in this way negatively their further development! In order to make use of the unique properties of SPCs we should not forget that they could be multi-phase but always remain one-component systems!

Studies on single polymer composites of poly(methyl methacrylate) reinforced with electrospun nanofibers with a focus on their dynamic mechanical properties

The dynamic mechanical properties of single polymer composites of poly(methyl methacrylate) (PMMA) rein- forced with electrospun PMMA nanofibers of different diameters are reported. The effect of electrospinning parameters on the morphology and diameters of the electrospun high molecular weight PMMA was investigated in order to obtain suitable diameters for the reinforcing fibers. Scanning electron microscopy (SEM) was used to study the morphology and diameters of the nanofibers produced at different electrospinning conditions. It was found that polymer solution concentration influ- ences the diameter of the electrospun nanofibers more than the spinning voltage and spinning distance. SEM analysis of the PMMA nanofibers showed that the fibers had a smooth, regular and cylindrical morphology with no beads and junctions. Effects of the processing temperature for the preparation of the single polymer composites via film stacking were investi- gated. Dynamic mechanical analysis showed a pronounced improvement in the storage modulus of the composites com- pared to the matrix.

The science and technology of hot compaction

The production and properties of single polymer composites is described, where the fibre and matrix phases are of identical chemical composition. The structure of the composites has been explored using mechanical tests, DSC and electron microscopy. Measurements of mechanical anisotropy, thermal expansion and impact behaviour are of especial interest. The commercialisation of the hot compacted materials is also described. Potential applications include the automotive industry, sports protection goods, loudspeaker cones and helicopter radomes.

The science and technology of hot compaction

The production and properties of single polymer composites is described, where the fibre and matrix phases are of identical chemical composition. The structure of the composites has been explored using mechanical tests, DSC and electron microscopy. Measurements of mechanical anisotropy, thermal expansion and impact behaviour are of especial interest.The commercialisation of the hot compacted materials is also described. Potential applications include the automotive industry, sports protection goods, loudspeaker cones and helicopter radomes.