Dynamic Thermomechanical Properties Research Articles

Unveiling the potential of self-healing and closed-loop recyclability in bio-based non-isocyanate polyurethane

The imperative shift towards sustainable production emphasizes the need for non-isocyanate polyurethanes (NIPUs) derived from biomass as a substitute for conventional petroleum-based polyurethanes. However, challenges persist in synthesizing NIPUs from renewable resources and addressing their recyclability post-service life. In this study, we report the synthesis of bio-based and closed-loop recyclable NIPU vitrimers using carbon dioxide (CO2), a vanillin derivative, and cystamine as bio-based feedstocks. The investigation examined the effect of the structure on the mechanical, thermal, and dynamic thermomechanical properties of bio-based NIPU vitrimers. The activation energy of the synthesized NIPUs was found to be relatively low (31.37 to 72.17 kJ/mol) after the incorporation of cystamine due to the presence of dual dynamic covalent bonds (disulfide and transcarbamoylation). As a result, the prepared bio-based NIPUs exhibited rapid self-healing and exceptional reprocessing efficiency (∼100 %). The mechanical properties of the reprocessed NIPUs could be restored to 99.5 % of their original values, highlighting remarkable reprocessing capabilities. The bio-based NIPU demonstrated closed-loop recyclability thanks to the dynamic disulfide bonds present in the vitrimer structure. This work offers an approach for the synthesis of bio-based NIPUS with closed-loop recyclability within the framework of sustainable materials.

Preparation and Evaluation of Epoxy Based Material for High Performance Electronic Packaging through the Surface Modification of Fillers

The continuous integration and refinement of electronic equipment results in the more stringent requirements for epoxy resin (EP) based materials, such as excellent heat dissipation and low coefficient of thermal expansion (CTE). In order to improve the dispersion of silica powder (SP) in EP and thus expand the application of EP in the field of electronic packaging, our research described in this paper adopted the KH-550 coupling agent to modify the surface of SP (m-SP). The effects of KH-550 coupling agent on the characteristics of the composites were investigated in terms of thermal, rheological, electrical insulation and mechanical properties. The results showed that when the content of KH-550 was 2 wt% of the fillers, the best modification effect was achieved, and the surface properties of the fillers were changed accordingly. In particular, the materials filled with m-SP exhibited lower viscosity end, better mechanical and electrical insulation properties. It was also found that the adding of the KH-550 had different effects on the thermal degradation, dynamic thermo-mechanical properties and the thermal deformation behavior of the materials. According to our study, the thermal conductivity and the CTE of m-SP/EP filled with 70 wt% of modified fillers were 0.787 W/m.K and 28.3 ppm/°C respectively, corresponding to a significant thermal conductivity improvement and low CTE.

A strong hydrogen bond bridging interface based on tannic acid for improving the performance of high-filled bamboo fibers/poly (butylene succinate-co-butylene adipate) (PBSA)biocomposites

Natural plant fiber-reinforced bio-based polymer composites are widely attracting attention because of their economical, readily available, low carbon, and biodegradable, and showing promise in gradually replacing petroleum-based composites. Nevertheless, the fragile interfacial bonding between fiber and substrate hinders the progression of low-cost and abundant sustainable high-performance biocomposites. In this paper, a novel high-performance sustainable biocomposite was built by introducing a high density strong hydrogen-bonded bridging interface based on tannic acid (TA) between bamboo fibers (BFs) and PBSA. Through comprehensive analysis, this strategy endowed the biocomposites with better mechanical properties, thermal stability, dynamic thermo-mechanical properties and water resistance. The optimum performance of the composites was achieved when the TA concentration was 2 g/L. Tensile strength as well as modulus, flexural strength as well as modulus, and impact strength improved by 22 %, 10 %, 15 %, 35 %, and 25 % respectively. Additionally, the initial degradation temperature(Tonset) and maximum degradation temperature(Tmax) increased by 12.07 °C and 14.8 °C respectively. The maximum storage modulus(E'), room temperature E', and loss modulus(E")elevated by 199 %, 75 %, and 181 % respectively. Moreover, the water absorption rate decreased by 59 %. The strong hydrogen-bonded bridging interface serves as a novel model and theory for biocomposite interface engineering. At the same time, it offers a promising future for the development of high performance sustainable biocomposites with low cost and abundant biomass resources and contributes to their wide application in aerospace, automotive, biomedical and other field.

Degradation of an underwater epoxy adhesive and its bonding to steel subjected to water or seawater immersion

Underwater adhesive is used to bond carbon fiber reinforced polymer (CFRP) composites to offshore or underwater structures. However, the long-term moisture exposure poses a challenge to the reliability and service life of the underwater adhesives. Therefore, the present article aims to provide a deep understanding of the durability of the underwater adhesive and the long-term bond performance between the CFRP and steel. The hygrothermal resistances of an underwater adhesive and CFRP-adhesive-steel double cantilever beam (DCB) immersed in deionized water and seawater at 25 °C, 40 °C, and 60 °C were investigated. The degradation mechanism was determined by the chemical characterization of the adhesive. Dynamic thermomechanical properties and tensile strength degraded significantly (≥62 %) before water uptake saturation due to adhesive plasticization. A high temperature (60 °C) can improve Mode I fracture toughness by at least 68 % due to an increase in the toughness of the adhesive.

Efficient Regulation of the Cross-Linking Structure in Polyurethane: Achieving Outstanding Processing and Mechanical Properties for a Wind Turbine Blade.

Although epoxy resin has been extensively used in the field of wind turbine blades, polyurethane has attracted much attention in recent years, due to its potential value of better fatigue resistance, lower processing viscosity and higher strength than epoxy resin blades. Herein, we construct a dense cross-linking structure in polyurethane (PU) based on different amounts of hydroxypropyl methacrylate (HPMA) with low processing viscosity and excellent mechanical properties. By increasing the content of HPMA, the thermal stability of PU is enhanced, but the micro-morphology does not change significantly. When the content of HPMA is 50 g (in 200 g copolymer), the PU sample PH-50 exhibits a viscosity of 70 MPa·s and a gelation time of 120 min at 25 °C, which is sufficient to complete processes like pouring and filling. By post-curing the PH-50 at 80 °C for 2 h, the heat distortion temperature can reach 72 °C, indicating the increase of temperature resistance. The PU copolymers also have excellent mechanical and dynamic thermo-mechanical properties due to the cross-linking structure between PU chains and poly-HPMA chains. Additionally, the PU copolymer has excellent compatibility with various glass fiber fabrics (GFF), showing a good match in the vacuum infusion experiment and great properties in the mechanical test. By compounding PH-50 with GFF, the composite with high strength is easily prepared for a wind turbine blade in various positions. The tensile strengths of the composites are all over 1000 MPa in the 0° direction. Such composites are promising for the future development of wind turbine blades that meet the stringent requirements for outstanding processing and mechanical properties.

Constructing a gradient modulus interface layer on the surface of carbon fibers to enhance the mechanical properties of carbon fiber/epoxy composites at different temperatures

A gradient modulus interface layer was designed between the carbon fiber and the epoxy by grafting the rigid polymer PPENK and the flexible polymer PEI. The influence of the interfacial modulus on the mechanical performance of carbon fiber/epoxy composite at different temperatures was analyzed. At room temperature, compared with the desized CF composite, the mechanical properties (interfacial shear, interlaminar shear, flexural strength, flexural modulus, and impact strength) of CF-PPENK-PEI composites were increased by 32.2 %, 11.4 %, 34.8 %, 24.2 % and 20.3 %, respectively. This improvement was attributed to the interfacial phase PPENK-PEI, which improved the roughness and polarity of the CF surface, increased wettability with the matrix, and buffered and balanced the modulus discrepancy between the CF and the epoxy. Atomic force microscopy (AFM) was confirmed the existence of a gradient modulus interface layer in CF-PPENK-PEI/epoxy composites. Notably, at 180 °C, the interlaminar shear strength (ILSS), flexural strength and flexural modulus of the CF-PPENK composite increased by 86.7 %, 92.5 % and 113.0 %, respectively, compared with the commercial CF composite, indicating better thermomechanical stability due to PPENK rigid heteroaromatic structures, which can maintain a high modulus at elevated temperature. Additionally, the dynamic thermomechanical properties of the composites were demonstrated the outstanding thermomechanical stability of the CF-PPENK/epoxy composites interface. Overall, this work provides a theoretical basis for preparing CF composites for use in high-temperature fields.

Achieving superior anti-corrosion properties of vinyl ester resin coatings via compositing with 3-methacryloxy propyl trimethoxysilane functionalized MXene nanosheets

Exposure of steel to harsh marine environment can cause serious corrosion, which significantly affects its durability. In this study, a novel two-dimensional MXene nanosheets were functionalized with 3-methacryloxy propyl trimethoxysilane (γ-MPS@MXene) followed by introducing into the vinyl ester resin (VER) through solution blending method to enhance the anti-corrosion properties of the coatings. The effects of γ-MPS@MXene incorporation on the mechanical properties, thermal stability, dynamic thermo-mechanical properties, UV aging resistance, anti-corrosion properties of the VER nanocomposites were systematically investigated. The optimum tensile strength, elastic modulus, hardness, thermal stability and UV aging resistance of γ-MPS@MXene VER nanocomposites can be achieved when composited with 0.08 wt% γ-MPS@MXene. The electrochemical impedance spectroscopy(EIS) results demonstrate the introduction of γ-MPS@MXene nanosheets into the VER enhanced the anti-corrosion properties of the composites coating remarkablely and the anti-corrosion mechanism was also revealed. The favourable interfacial interaction between γ-MPS@MXene and VER matrix through covalent cross-linking diminished interfacial defects of the composite coating and was also beneficial to enhancement of the compatibility, the well-dispersed γ-MPS@MXene in VER created a “labyrinth effect”, which prolonged the diffusion path of corrosive medium to the carbon steel substrate. This research provides a promising strategy for the fabrication of heavy anti-corrosion nanocomposite resin coatings, which can realize long-term corrosion protection of metal substrates.

Effects of Surface Properties of Fiber on Interface Properties of Carbon Fiber/Epoxy Resin and Its Graphene Oxide Modified Hybrid Composites.

In the present study, surface properties of three types of carbon fibers (CCF300, CCM40J, and CCF800H) on the interface properties of carbon fiber/epoxy resin (CF/EP) were analyzed. The composites are further modified by graphene oxide (GO) to obtain GO/CF/EP hybrid composites. Meanwhile, the effect of the surface properties of CFs and the additive graphene oxide on the interlaminar shear properties and dynamic thermomechanical properties of GO/CF/EP hybrid composites are also analyzed. The results show that the higher surface oxygen-carbon ratio of carbon fiber (CCF300) has a positive effect on improving the glass transition temperature (Tg) of the CF/EP composites. The Tg of CCF300/EP is 184.4 °C, while the Tg of CCM40J/EP and CCF800/EP are only 177.1 °C and 177.4 °C, respectively. Furthermore, deeper and more dense grooves on the fiber surface (CCF800H and CCM40J) are more conducive to improving the interlaminar shear performance of the CF/EP composites. The interlaminar shear strength (ILSS) of CCF300/EP is 59.7 MPa, and that of CCM40J/EP and CCF800H/EP are 80.1 MPa and 83.5 MPa, respectively. For the GO/CF/EP hybrid composites, graphene oxide with abundant oxygen-containing groups is beneficial to improve the interfacial interaction. Graphene oxide can significantly improve the glass transition temperature and interlamellar shear strength of GO/CCF300/EP composites fabricated by CCF300 with a higher surface oxygen-carbon ratio. For the CCM40J and CCF800H with lower surface oxygen-carbon ratio, graphene oxide has a better modification effect on the glass transition temperature and interlamellar shear strength of GO/CCM40J/EP composites fabricated by CCM40J with deeper and finer surface grooves. Regardless of the type of carbon fiber, the GO/CF/EP hybrid composites with 0.1% graphene oxide have the optimized interlaminar shear strength, and the GO/CF/EP hybrid composites with 0.5% graphene oxide have the maximum glass transition temperature.

Reinforcement of polyamide 6 with carbon fiber surface modified by a polar cross-linked network interfacial phase

Carbon fiber-reinforced polyamide 6 (CF/PA6) composite materials have low relative density, high specific strength, and high specific modulus. However, the surface of the CF is smooth and chemically inert, resulting in poor interfacial adhesion in CF/PA6 composites, thereby limiting its application range. Herein, an epoxy resin emulsifier with hydrophilic ends and lipophilic middle was synthesized. After sizing, the surface chemical activity and roughness of the CF were higher. The tensile strength of the prepared CF/PA6 composite material was increased by 38.6%, and the impact strength was increased by 26.4%. By testing the tensile strength and wettability of the CF, as well as the dynamic thermomechanical properties and rheological behavior of the CF/PA6 composites, the influence of the sizing agent on the properties of CF and the interfacial properties of CF/PA6 composites was evaluated, and its mechanism of action is discussed herein.

The Influence of Nano-CaCO3 on the Mechanical and Dynamic Thermo-Mechanical Properties of Core–Shell Structured Wood Plastic Composites

Using bamboo residue and high-density polyethylene (HDPE) as the main raw materials, core–shell structured wood plastic composites (WPCs) with nano-CaCO3 filling shell were prepared by coextruded technology. The effect of nano-CaCO3 contents on the flexural properties, impact strength and dynamic thermo-mechanical properties of the core–shell structured WPCs were investigated. And the value of core–shell interface interaction parameter was calculated by dynamic thermodynamic parameters. The results showed that the flexural strength increased by 48.1% and 40.3% when it was loaded with 10%–15% nano-CaCO3, compared to the HDPE shell composites, respectively. While nano-CaCO3-filled HDPE shell had lower impact strength in comparison with HDPE shell, the field emission scanning electron microscope revealed proper interfacial adhesion between the core and shell layers. The storage modulus of core–shell structured WPCs increased as nano-CaCO3 contents increased, but the values were lower than that of the HDPE shell. Addition of nano-CaCO3 caused an increase in the glass transition temperature (Tg) of the core–shell structured WPCs, loss factor (tanδ) of the core–shell structured WPCs decreased. The value of the core–shell interface interaction parameter of the core–shell structured WPCs increased significantly after the nano-CaCO3 loading reached 15%, which was consistent with the bending test results. These findings demonstrate that the core–shell structured WPCs have excellent properties filling with nano-CaCO3 in the shell layer, and bamboo residue is added to the core layer.

Designing a Coupling Agent with Aliphatic Polyether Chain and Exploring Its Effect on Silica/Natural Rubber Nanocomposites under the Action of Non-Rubber Contents.

In order to prepare engineering tires with lower rolling resistance and better wet slip resistance in a more environmentally friendly way. In this study, a series of low volatile organic compound (VOC) Mx-Si69 coupling agents (x = 1, 2, 3, 4, 5, 6, which means the number of ethoxy group in bis-(γ-triethoxysilylpropyl)-tetrasulfide (Si69) substituted by the aliphatic polyether chain) were applied to silica/NR nanocomposites to prepare tire tread with excellent performance. Firstly, M1-Si69 was substantiated as the best choice of Mx-Si69 and Si69 to achieve comprehensive optima in the mechanical properties of silica/NR nanocomposites characterized by dynamic and static mechanical properties. Afterwards, the modification of silica with M1-Si69 induced by Non-Rubber Contents (NRCs) in silica/NR nanocomposites was revealed by comparing the filler network, micromorphology, and mechanical properties of isoprene rubber (IR) and NR nanocomposites. Furthermore, compared with Si69, the M1-Si69 coupling agent was found to conspicuously reduce the energy loss and improve the safety performance of engineering tires according to evaluations of the rolling resistance and dynamic thermomechanical properties of the silica/NR nanocomposites. Finally, the critical function of M1-Si69 in reducing ethanol (a kind of volatile organic compound (VOC)) emissions from the reaction of coupling agent and silica was disclosed by gas chromatography-mass spectrometry.

Enhanced mechanical property of continuous carbon fiber/polyamide thermoplastic composites by combinational treatments of carbon fiber fabric

To fabricate continuous carbon fiber (CF)/polyamide (PA 6) thermoplastic composites with high strength and stiffness, combinational treatments of liquid phase oxidation, coupling agent, and coating were adopted to improve the surface activity of CF fabric and interfacial bonding with PA 6 matrix. The mechanical properties, dynamic thermomechanical properties, microstructure, and hydrothermal aging behavior of the CF/PA 6 composites were studied. The XPS results showed the N, O, and Si elements as well as the C–O, CO, and C–Si groups were significantly increased on the CF surface, indicating the improvement of chemical activity and KH550 effectively grafted. The tensile strength significantly increased from 396 MPa to 480 MPa, by 21.2%, and Young's modulus increased from 38.6 GPa to 47.9 GPa, by 24.1%, respectively. The result of the damp heat aging test in 240 h showed the retention rate of flexural strength and ILSS were 66% and 67%, respectively.

Circularity in polymers: addressing performance and sustainability challenges using dynamic covalent chemistries.

The circularity of current and future polymeric materials is a major focus of fundamental and applied research, as undesirable end-of-life outcomes and waste accumulation are global problems that impact our society. The recycling or repurposing of thermoplastics and thermosets is an attractive solution to these issues, yet both options are encumbered by poor property retention upon reuse, along with heterogeneities in common waste streams that limit property optimization. Dynamic covalent chemistry, when applied to polymeric materials, enables the targeted design of reversible bonds that can be tailored to specific reprocessing conditions to help address conventional recycling challenges. In this review, we highlight the key features of several dynamic covalent chemistries that can promote closed-loop recyclability and we discuss recent synthetic progress towards incorporating these chemistries into new polymers and existing commodity plastics. Next, we outline how dynamic covalent bonds and polymer network structure influence thermomechanical properties related to application and recyclability, with a focus on predictive physical models that describe network rearrangement. Finally, we examine the potential economic and environmental impacts of dynamic covalent polymeric materials in closed-loop processing using elements derived from techno-economic analysis and life-cycle assessment, including minimum selling prices and greenhouse gas emissions. Throughout each section, we discuss interdisciplinary obstacles that hinder the widespread adoption of dynamic polymers and present opportunities and new directions toward the realization of circularity in polymeric materials.

Flexural and shape memory properties of unidirectional glass and carbon fibers reinforced hybrid shape memory polymer composites

There has been a lot of research on hybrid composites, but most of the research is limited to traditional composites. As a kind of thermo-responsive material, the mechanical properties of shape memory polymer composites (SMPCs) vary dramatically with temperature, so researches on the isothermal mechanical properties of hybrid SMPCs under different temperatures are necessary. This paper investigates the flexural and shape memory performances of carbon fiber (CF) and glass fiber (GF) reinforced hybrid SMPCs. After determining the lamina properties of CF and GF laminae at different temperatures, the flexural properties of hybrid SMPCs were predicted by simulation and theoretical calculations, which agreed well with the subsequent experimental results. The failure modes, dynamic thermomechanical properties, and shape memory properties of hybrid SMPCs with different fiber stacking configurations at different temperatures were then investigated. Finally, the effects of hybrid ratios on the flexural moduli of hybrid SMPCs at different temperatures were studied.

High content of spherical nanosilica filled epoxy resin master batch with low viscosity and superior thermomechanical performance

Spherical nanosilica is reckoned as an indispensable filler in electronic encapsulation to improve the thermomechanical performance of epoxy resin matrix. How to achieve higher content and better dispersion of spherical nanosilica in epoxy resin remains a big challenge. Here, Surface-modified spherical nanosilica was prepared on the basis of Stöber method in the presence of binary silane coupling agents as surface modifier. High content of as-modified spherical nanosilica was introduced into bisphenol F epoxy resin (denoted as EP) matrix by one-step liquid-phase method to afford SiO2/EP master batch. The viscosity, thermal stability and dynamic thermo-mechanical properties of SiO2/EP composites with different filler contents derived from SiO2/EP master batch were systematically investigated. Findings indicate that organosilanes grafted onto the surface of silica nanoparticles contribute to improving their compatibility and dispersibility within EP matrix, leading to a relatively low level of viscosity of EP-matrix composites especially under a high nanofiller dosage and improving their dynamic thermomechanical properties and thermal expansion stability as well. Moreover, SiO2/EP master batch made from liquid-phase method exhibits better performance compared with that prepared by physical blending way. It is a facile way to prepare EP master batch with high filler content, low viscosity and superior performance, meanwhile brings processing convenience for application in electronic encapsulation.

The single or combined treatment effect of jute surface modification on mechanical and thermomechanical properties of jute/PLA laminated composites

Jute fibers are commonly used as reinforcement in composite materials manufacture due to its excellent mechanical properties. In this study, alkali (NaOH) and silane coupling agent KH570 treatment were conducted on component jute nonwovens to improve the bonding strength of jute/PLA composite interface. The jute/PLA composites were prepared from treated jute nonwovens and PLA films by molding method. The results show that alkali treatment can significantly improve the tensile, flexural and dynamic thermomechanical properties of jute/PLA composites. The composites treated with 1% NaOH exhibits the maximum tensile strength while the composites treated with 5% NaOH presents the maximum flexural strength and the minimum loss in the dynamic thermo-mechanical process. Moreover, the tensile and flexural strength of the composite treated with the combination of 5% NaOH-5% KH570 is significantly stronger than that when they act alone. This research can provide an optimal treatment strategy for the jute/PLA degradable composites with higher mechanical and thermos-mechanical tolerance.

Investigation into Thermomechanical Response of Polymer Composite Materials Produced through Additive Manufacturing Technologies.

This paper presents the static mechanical behavior and the dynamic thermomechanical properties of four market-available reinforced and non-reinforced thermoplastics and photopolymer materials used as precursors in different additive manufacturing technologies. This article proposes a characterization approach to further address development of aeronautic secondary structures via 3D-printed composite materials replacing conventional manufactured carbon fiber reinforced polymer (CFRP) composites. Different 3D printing materials, technologies, printing directions, and parameters were investigated. Experimental results showed that carbon-reinforced ONYX_R material exhibits a transition point at 114 °C, a 600 MPa tensile strength, and an average tensile strain of 2.5%, comparable with conventional CFRP composites manufactured via autoclave, making it a suitable candidate for replacing CFRP composites, in the aim of taking advantage of 3D printing technologies. ONYX material exhibits higher stiffness than Acrylonitrile-Butadiene-Styrene Copolymer (ABS), or conventional Nylon 6/6 polyamide, the flexural modulus being 2.5 GPa; nevertheless, the 27 °C determined transition temperature limits its stability at higher temperature. Daylight High Tensile (further called HTS) resin exhibits a tensile strength and strain increase when shifting the printing direction from transversal to longitudinal, while no effect was observed in HighTemp DL400 resin (further called HTP).

Curing behavior of sodium carboxymethyl cellulose/epoxy/MWCNT nanocomposites

The surfactant-assisted preparation of carbon nanotube (CNT)/polymer composites has attracted the attention of scientists around the world. Here, CNT/epoxy nanocomposites were prepared using sodium carboxymethyl cellulose (CMC). The effect of CMC on the curing behaviors of epoxy resin (E44) and CNTs/E44 was studied using differential scanning calorimetry (DSC). The curing kinetics of the CMC/CNTs/E44 systems were examined using methods where the activation energy (E) is a constant and where E is a variable, respectively. The change of E with the conversion (α) was calculated using the Starink isoconversional method. For the E44 system, a significant variation of E was observed when the conversion increased from 0.05 to 0.95. The E variable method was introduced to this system to describe this phenomenon. In contrast to the method where E is a constant, the E variable method has better agreement with the experimental data. With these two methods, the curing kinetics of the CMC/CNTs/epoxy system can be understood comprehensively and accurately. Ultimately, the dynamic mechanical properties of neat E44, CMC/E44 and CMC/CNTs/E44 were investigated and compared, which showed that CMC/E44 had a higher storage modulus (Em) than the neat E44 and CMC/CNTs/E44 systems, and the CMC/CNTs/E44 system had a higher glass transition temperature (Tg) and damping factor (tan δ) than the neat E44 and CMC/E44 systems.

The influence of white mud on the water absorption, surface wettability, mechanical, and dynamic thermomechanical properties of core–shell structured wood-plastic composites

The influence of white mud on the water absorption, surface wettability, mechanical, and dynamic thermomechanical properties of core–shell structured wood-plastic composites

Rheological, electrical, and dynamic thermomechanical properties: Comparison between multiwall and double-wall carbon nanotubes in polylactide and polyamide 11

In this study, multiwall carbon nanotubes (MWCNTs) and double-wall carbon nanotubes (DWCNTs) have been dispersed in polylactide (PLA) and polyamide 11 (PA11) using an internal mixer. Rheological characterization confirmed the formation of carbon nanotube (CNT) networks in PLA and PA11 attributed to well-dispersed CNTs in the respective matrices. A lower rheological percolation threshold of PLA/MWCNT nanocomposites (less than 0.5 wt. %) compared to PA11/MWCNT nanocomposites (about 2 wt. %) confirmed the greater affinity of CNTs for PLA. The threshold for DWCNTs was below 0.5 wt. % in PLA and between 0.5 and 1 wt. % in PA11. PLA-based nanocomposites also showed higher electrical conductivity values compared to PA11-based nanocomposites. Nanocomposites containing DWCNTs exhibited higher electrical conductivities compared to those containing MWCNTs due to the higher aspect ratio of DWCNTs. Dynamic mechanical thermal analysis showed enhanced storage modulus values and reduced damping behavior with increasing content of CNTs for both polymers.