This work attempts to study the effects of the addition of graphene nanoplatelets (xGNP) on the rheology properties of new version of polyurethane copolymer with 1,5 pentane diol as chain extender , containing a high amount of hard blocks. Two- step polymerisation was employed to synthesise this kind of polymer. The thermal and electrical conductivity of this copolymer was also investigated. Meanwhile, the rheology response has been analysed by measuring the viscosity It was found that the viscosity increases by 68% and 2 × 105% at loadings of 0.5 wt.% and 15 wt.% of xGNP, respectively, compared with that of neat polyurethane copolymer. This means that the melt viscoelastic behaviour of highly rigid polyurethane copolymer (HRPUC) is influenced by the presence of xGNP contents, transforming the behaviour of nanocomposite from liquid-like to solid-like. This result was attributed to the network formation and interaction between hard segments of the HRPUC structure and xGNP due to strong shear thinning behaviour. In addition, the thermal conductivity of HRPUC increases to 0.97 W m−1.k (410%), electricity conductivity rose to 102 s m−1 (1000%). SEM morphology images showed overall dispersion of xGNP in the HRPUC, implying a reduction in the interspacing of flakes with increasing xGNP concentration. Further investigation into HRPUC morphology and its nanocomposites was conducted using the TEM method, illustrating that the xGNP stacking resulted from poor ability to disperse at greater loadings of xGNP.

The current work investigates the effect of the addition of graphene nanoplatelets (GNPs) and graphene oxide (GO) to high hard-segment polyurethane (75% HS) on its thermal, morphological, and mechanical properties. Polyurethane (PU) and its nanocomposites were prepared with different ratios of GNP and GO (0.25, 0.5, and 0.75 wt. %). A thermal stability analysis demonstrated an enhancement in the thermal stability of PU with GNP and GO incorporated compared to pure PU. Differential Scanning Calorimetry (DSC) showed that both GNP and GO act as heterogeneous nucleation agents within a PU matrix, leading to an increase in the crystallinity of PU. The uniform dispersion and distribution of GNP and GO flakes in the PU matrix were confirmed by SEM and TEM. In terms of the mechanical properties of the PU nanocomposites, it was found that the interaction between PU and GO was better than that of GNP due to the functional groups on the GO’s surface. This leads to a significant increase in tensile strength for 0.5 wt. % GNP and GO compared with pure PU. This can be attributed to interfacial interaction between the GO and PU chains, resulting in an improvement in stress transferring from the matrix to the filler and vice versa. This work sheds light on the understanding of the interactions between graphene-based fillers and their influence on the mechanical properties of PU nanocomposites.

The remarkable structural features of organic modified montmorillonite particles (OMMT) enable them to complete their important role in enhancing different properties of polyurethane copolymer with 75 wt.% hard segments (PUC/75). Based on the melt intercalation approach, various amounts of OMMT were incorporated into PUC/75 solution followed by the injection moulding process. It is essential to mention that the synthesized PUC/75 in this work relied on using 1,5-Pentanediol as a chain extender in order to produce a long-term and thermal-stable PUC successfully. The effect of incorporating various loading of OMMT on rheological properties of neat PUC/75 and its nanocomposites was investigated. The structure of PUC/OMMT was studied using X-ray diffraction (XRD) and scanning electron microscopy. Additionally, differential scanning calorimetry (DSC) thermograms were utilized to investigate OMMT effect on the thermal transitions and crystallinity of resultant PUC nanocomposites. Interestingly, the dynamic rheological analysis exhibited a remarkable increase in melt rheology behaviour with increasing OMMT loading compared to neat PUC/75. This could imply a good interaction between the functional group on the surface of OMMT and PUC/75 domains; particularly hard domains, herein the DSC results showed moderate improvement in melt temperature (Tm) of PUC/OMMT nanocomposite. However, a decline in crystalline temperature (Tc) was also seen due to aggregation of OMMT, especially at higher OMMT loading. While XRD results exhibited a slight shifting in crystalline peaks of PUC nanocomposites relative to neat PUC/75.

The purpose of preparing the review manuscript is to highlight the importance of the physical specifications of the most important of inorganic fillers such as "carbon black" and "silica" that have good physical specifications as surface area, particle size distribution and surface chemistry. Moreover, study the effect of these specifications on the resistance of vulcanized rubber compound for swelling, which is one of the disadvantages to determine the expansion of its uses in industrial applications through the review of many types of research in this area. The results proved that there is a strong relationship between the curing characteristics of the rubber compound such as the time of curing, the scorch time in addition to the "curing rate index' (CRI) and mechanical properties especially the tensile strength and "density of cross-links" for reducing the swelling rate to the minimum. By increasing the "density of cross-links" and improve the specifications of vulcanization and mechanical specifications.

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