*1.1.1 In-situ polymerization*

Here the scheme, constitutes the mixing of a monomer and graphene fillers, particularly in the presence of a catalyst (s). The stage is then generally followed by polymerization initiation through heat or radiation [1]. The utility of epoxy in in-situ polymerization is an excellent example [2]. However, fabrication done by this scheme yields some polymer/graphene composites like graphene/polystyrene (PS) [1], graphene/polyaniline (PANI) composite [3], and graphene/silicone composites [4]. Significance of this method is the strong interaction between the filler and the polymer matrix. This leads to a rapid stress transfer, enabling a quick formation of the homogeneous dispersion. In addition, fillers constitute homogeneity in their distribution. High filler loading in polymer matrices is also achieved through In-situ polymerization. Meanwhile, the mixture becomes more viscous during polymerization, and the ongoing process suffers difficulties, causing ultimate hindrance for the loading fraction [5]. Usually solvent is the prime option in the current method most of time in some cases, but it extensively raises the need for the removal of solvent [6].

#### **Figure 1.**

*General fabrication routes for graphene polymer hybrids (GCHs).*

*Graphene Based Functional Hybrids: Design and Technological Applications DOI: http://dx.doi.org/10.5772/intechopen.108791*

### *1.1.2 Melt intercalation technique*

Melt intercalation method incorporates designing of graphene in the molten state with the polymer matrix, thereby eliminating the need of solvent. High shear mixing with accelerated temperature results in the homogeneity of polymers and graphitic materials mixing. Thermoplastic composites are the most manufactured yield of this method. This method carries some of the graphene/polymer composites including exfoliated graphite/polypropylene nanocomposites [7], polystyrene/graphite nanosheet composites [8], polyethylene terephthalate (PET)/graphene nanocomposites [9], etc. On the contrary, this scheme has some discrepancies too, like poor dispersity and fillers distribution, than rest of methods. In addition, possibilities for breakage of graphene sheets and defects are comparatively much higher than rest of methods [10].
