Conductive polymer composites (CPCs) with the ability to maintain high conductivity whilst remaining flexible at various operating temperatures and conditions have gained interest as potential materials for electronic interconnect applications. The ability of a polymer matrix to conduct electricity is mainly dependent on the conductive filler loadings as well as the formation of network paths within the CPCs. The main aim of this research work was to establish and understand the correlation between the network structure formation and mechanical properties of linear low-density polyethylene/copper (LLDPE/Cu) and liquid silicone rubber/copper (LSR/Cu) CPCs. Various techniques such as electron microscopy, thermal studies, four-point probe, and tensile testing were employed in this study. Furthermore, selected samples were characterized and tested using synchrotron micro-x-ray fluorescence (XRF) technique and dynamic mechanical analysis (DMA). It was found that the electrical conductivity of the CPCs increased with increasing filler loadings. Addition of Cu filler had a marginal effect on the tensile strength of both LLDPE/Cu and LSR/Cu CPCs. Nevertheless, it was found that the elongation at break for LLDPE/Cu consistently increased with the addition of Cu whereas, for LSR/Cu samples, the elongation at break decreased with the addition of Cu at various loadings. The scanning electron microscopy (SEM) micrographs obtained show that the particles of Cu were closer to one another at higher filler loadings. The data obtained revealed the potential for utilizing CPCs as flexible interconnects suitable for advanced electronic applications.

The flexibility of conductive polymer composites (CPCs) has become an area of interest, especially to the electronic industry for the application of interconnects. The incorporation of maleic anhydride-grafted polypropylene (MAPP) within polypropylene (PP)/ carbon black (CB) conductive polymer composites as a compatibiliser was essential in order to improve the interaction between conductive filler and polymer matrix. The PP/CB and PP/CB/MAPP (5 wt% MAPP) CPCs at various loading of CB were prepared using an internal mixer. The prepared composites were then hot pressed to form suitable size samples for characterisation and testing. It was found that the electrical conductivity of the composites was increased with increasing CB loadings due to formation of network path. Moreover, the electrical conductivity for CPCs with the additions of MAPP was further increased compared to without MAPP. The electrical conductivity of PP/CB/MAPP with 5 wt% of CB loading achieved 78.5 μS/cm by an increment of 6.4 % compared to PP/CB with 5 wt% of CB loading. However, increasing CB loading led to a decrease in tensile strength and elongation at break of PP/CB and PP/CB/MAPP composites. Nevertheless, additions of MAPP had improved the CPCs tensile strength. The addition of MAPP in 5 wt% of CB loading in CPC recorded a tensile strength of 25.93 MPa, an increased by 4.17 % compared to PP/CB composite. The optimum tensile and electrical properties obtained were at 5 wt% of CB loading in PP/CB/MAPP composite as it has higher tensile strength and achieved the percolation threshold. Furthermore, the thermal analysis carried out using differential scanning calorimetry (DSC) found that the crystallinity of PP was affected and the scanning electron microscopy (SEM) showed the distribution of CB particles within PP matrix that led to the changes observed in the mechanical properties and electrical conductivity of CPCs.

In recent years, the research and development in conductive polymer composites (CPCs) had gained considerable interests in both industry and academia as potential materials for electronic interconnects. These composites require to have the ability to conduct electric while maintaining sufficient flexibility while withstanding the bending, twisting, or stretching during service. To achieve the desired composite properties, the processing method and the parameters involved plays important role and ought to be investigated. In this study, the effect compounding parameters on the preparation of linear-low density polyethylene/carbon black (LLDPE/CB) polymer composite were carried out. Factors namely filler loadings, screw speed and maximum barrel temperatures were selected and their effects on the tensile properties and conductivity were analyzed in this research. It was observed that the increasing of filler loadings from 5 wt.% to 10 wt.% has increased the electrical conductivity from 1.11×10–2 S/m to 1.46×10–2 S/m. The pareto chart shows that the filler loading was important factors to the result of composite conductivity. Moreover, the main effect plot shows that the filler loading has the highest mean effect on conductivity as it is important for the formation of conducting path in composite. It was also established that the pareto chart also shows that filler loading and barrel temperature have the highest significant effect on LLDPE/CB polymer composite tensile properties. The changes in the combinations of factors affect the tensile properties as revealed by the main effect plots for LLDPE/CB CPCs.

The insulating nature of a polymer can be changed to electrically conductive by incorporating conductive fillers within the polymer matrix to form a conductive polymer composite (CPC). One of the potential application of CPCs are in the area of flexible electronic interconnect application. Nevertheless, the correlation between the electrical conductivity and mechanical properties of CPCs such as tensile was found to be limited. Therefore, this paper is aimed to report the preliminary investigation on the correlation between conductivity and mechanical properties of a low-density polyethylene (LDPE) incorporation with conductive filler which is carbon black (CB. It was observed that the tensile strength was decreased by up to 29.4% and the elongation of break was decreased by up to 90.6% at higher CB loading compared to pure LDPE. Nonetheless, the modulus of elasticity and the electrical conductivity of the composites were increased by up to 150.5% and 16.4% at higher CB loading respectively. Moreover, it was found that the effect of CB additions on the tensile modulus was greater compared to the conductivity of the CPCs.

Polymeric materials are known to have insulating properties in general. Nevertheless, the insulating nature of polymers can be turned into electrically conductive by adding conductive fillers subjected to their critical filler loading or percolation threshold. In this study, the effects of various conductive fillers additions, namely copper, silver, and carbon black, on the percolation threshold of linear low-density polyethylene conductive polymer composites were investigated. The mechanical properties were determined using the tensile test, and the electrical conductivity was determined using the four-point probe. The incorporation of conductive fillers generally had an impact on the tensile strength and elongation at the break of the linear low-density polyethylene conductive polymer composites. Nonetheless, it was found that the electrical conductivity of all composites increases where the percolation threshold is estimated for carbon black at 2 wt% and for Ag and Cu at 6 wt% of filler additions.

Low-linear density (LDPE) and copper (Cu) were used as main polymer matrix and conductive filler in order to produce electrically conductive polymer composites (CPC). The selection of the matrix and conductive filler were based on their due to its excellence properties, resistance to corrosion, low cost and electrically conductive. This research works is aimed to establish the effect of compounding parameter on the electrical conductivity of LDPE/Cu composites utilising the design of experiments (DOE). The CPCs was compounded using an internal mixer where all formulations were designed by statistical software. The scanning electron micrograph (SEM) revealed that the Cu conductive filler had a flake-like shape, and the electrical conductivity was found to be increased with increasing filler loading as measured using the four-point probe technique. The conductivity data obtained were then analysed by using the statistical software to establish the relationship between the compounding parameters and electrical conductivity where it was found based that the compounding parameters have had an effect on the conductivity of the CPC.

Conductive polymer composite (CPCs) has the potential to be one the material that can be used in electronic interconnect applications. In recent years, it had attracted number of researchers to explore and understand the structure-properties of flexible CPCs conductivity and mechanical properties to suits their final applications. It is worth mentioning that for polymer to conduct electricity, the key aspect to tackle in CPCs is their percolation threshold. The percolation threshold is known as the point where material changes it properties from insulating to conductive. Hence, there are many models and theories widely published by other researchers within the area that can be used to predict electrical conductivity and tensile properties which are based on percolation threshold. In this paper, we briefly review several models namely classic percolation threshold and McLachlan for electrical conductivity; and Pukanszky and Ouali models for the mechanical percolation. The effect of particle size in percolation threshold was also reviewed in this paper. The primary aim for this paper is to establish the correlation between conductivity and mechanical properties in CPCs using the aforementioned models. This will enable researchers to understand the behavior and ultimately predict the performance of flexible CPCs for interconnect applications.

The development of conductive polymer composites along with their advantages are rapidly growing to meet current demands in electronic applications. There are many types of matrix and filler that had been extensively researched in order to find the most suitable materials that can be utilized for electronic interconnect applications. Previous works carried out by researchers within the field revealed that by using melt blending techniques such as twin screw compounding and compression moulding can be used to develop conductive composite polymer such as from polypropylene (PP) incorporated with graphite as conductive filler. The conductivity of the composite can be measured using the 4-point probe technique. This short review aims to provide the latest insight in the area of electrically conductive polymer composites focused on the types of matrix and filler, processing and utilisation in electronic interconnect and other potential applications.

Conductive films based on natural polymers may find potential in food packaging and biomedical applications owing to their advantages of biodegradability and biocompatibility. This work demonstrated conductive composite films from hydroxyethyl cellulose (HEC) incorporated with graphite prepared by solution casting. Fourier Transform Infrared (FTIR) spectra confirmed the absence of covalent bond between the HEC matrix and graphite. The electrical conductivity of the composite films with various concentrations of graphite was investigated by a four-point probe. We observed that the conductivity of the HEC film increased remarkably from 10−8 S/cm to 10−5 S/cm upon addition of graphite. The highest conductivity of 9.44 x 10−5 S/cm to 10−5 S/cm upon addition of graphite. The highest conductivity of 9.44 x 10−5 S/cm was obtained for the film with 30 wt% of filler and further addition of filler reduced the conductivity. The correlation between conductivity and crystallinity was elucidated by X-ray diffraction (XRD) patterns. The difference in d-spacing values between HEC and HEC/Graphite films and the decrement of crystallinity percentage suggest that the rearrangement of ordered HEC crystalline structure was perturbed by the filler resulting in reduction of crystallinity phase. The tensile properties results clearly show that the incorporation of graphite into HEC films has reduced the tensile strength which is in agreement with the obtained electrical conductivity and crystallinity percentage.