## 4 Influence of QACs on Thermo-Mechanical Properties of Polymer Blends and Polymer Composites
### Influence of QAILs on Polymer Composites
Furthermore, the mechanical properties, such as tensile strength and tensile modulus of the composites increased by up to 26% and 62%, respectively, compared to the neat composite. This is because of the composites having strong and stiff properties, as well as BmimCl acted as a coupling agent or compatibilizer for the composites. However, the tensile extension of the composites decreased because the motion of agarose molecular chains was restricted by the talc filler [19]. The result also confirmed that the stiffness property of the composites increased with the presence of compatibilizer, which enhanced the rigidity of the composites, thus moving the tensile extension to lower values. On the other hand, QAIL like EmimAc (chemical structure is shown in Figure 6) has been applied for compatibilization of DGEBA epoxy/Chitin composites [21]. The application of EmimAc influenced the degradation temperature, glass transition temperature, tensile strength, tensile modulus, tensile extension, and impact strength of the composites (Table 9). The degradation temperature of the composites remains unchanged because of the small content of chitin in the composites; thus, the overall thermal degradation behavior is similar to the neat DGEBA epoxy matrix. Nonetheless, the glass transition temperature of the composites increased by up to 9.0% compared to the neat matrix. This is attributed to the presence of chitin, which restricted the mobility of DGEBA epoxy chains prompted by intermolecular hydrogen bonding [21]. Moreover, the mechanical properties, such as tensile strength, tensile modulus, tensile extension, and impact strength of the composites increased by up to 34%, 8.4%, 80%, and 91%, respectively, in comparison with the neat matrix. This is because of the better dispersion of chitin filler within the DGEBA epoxy matrix with the presence of EmimAc [21]. Besides, QAIL like BmimPF\({}_{6}\) (chemical structure is shown in Figure 6) has been applied for compatibilization of PU/SiO\({}_{2}\) composites [23]. The application of BmimPF\({}_{6}\) influenced the degradation temperature, glass transition temperature, thermal conductivity, flexural strength, and flexural extension of the composites (Table 9). The thermal properties, such as degradation temperature and glass transition temperature of the composites increased by up to 10% and 13%, respectively, compared to the neat PU/SiO\({}_{2}\) composite. This is attributed to the presence of BmimPF\({}_{6}\) that has significantly enhanced the thermal stability of the composites. Nevertheless, the thermal conductivity of the composites decreased because of the low thermal conductivity of SiO\({}_{2}\) filler, which is well dispersed in the cell walls of the PU matrix [23]. In addition, the BmimPF\({}_{6}\)-compatibilized composites improved the interfacial adhesion between PU and SiO\({}_{2}\), which reduced the heat transfer on the matrix, thus decreasing the thermal conductivity of the composites. The flexural strength of the composites increased by up to 15% in comparison with the neat composite. This is because of the reinforcing effect of SiO\({}_{2}\) and compatibilization effect of BmimPF\({}_{6}\). However, the flexural extension of the composites decreased because of the existence of SiO\({}_{2}\) aggregates that acted as defects within the PU matrix [23]. The aggregates normally exist at high content of SiO\({}_{2}\) filler in the matrix. Hence, the formation of aggregates can be avoided or minimized during the preparation of the composites. The compatibilization by applying QAILs is not only limited to conventional polymer composites, but they can also be applied in polymer nanocomposites as QASs. BmimCl is applied for compatibilization of RC/MMT nanocomposites [25]. The application of BmimCl influenced the degradation temperature, tensile strength, tensile modulus, and tensile extension of the nanocomposites (Table 9). The degradation temperature of the nanocomposites increased by up to 154% compared to the neat RC matrix.