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Imidazolium-functionalized polyurethane (IPU) functionalized multi-walled carbon nanotubes (CNTs) was used to control interfacial distribution and compatibilization of CNTs, and enhance electromagnetic interference (EMI) shielding and mechanical properties of poly(lactic acid)/polycaprolactone (PLA/PCL) based composites. IPU facilitated the uniformly dispersion of CNTs and induced the selectively location of CNTs at the interface and PCL phase, which is beneficial to build more effective three-dimensional network structure at the co-continuous interphase. The EMI shielding properties for the PLA/PCL/8CNT/0.8IPU composites have been evidently increased to 35.6 dB. Meanwhile, the elongation at break and the notched impact strength of the PLA/PCL/8CNT/0.8IPU composite reached 307.8 % and 51.3 kJ/m2, respectively, which are increased by 27 and 53 % of PLA/PCL/8CNT because of the compatibilization effect of IPU and the distribution of CNTs. This work presented a promising prospect of polymer-based composites with satisfactory EMI shielding and mechanical properties. • IPU modified CNTs are selectively located at the interface and PCL phase. • The double-percolated structure contributed to the highly improved properties. • IPU modified CNTs served as interface compatibilizer for excellent toughness. • The EMI SE and elongation at break of PLA/PCL/8CNT/0.8IPU are 35.6 dB and 307.8 %. [ABSTRACT FROM AUTHOR]

In order to synchronously improve mechanical and flame retardant properties of polylactide/poly(butylene adipate- co -terephthalate) (PLA/PBAT) composites, a series of multifunctional composites containing multi-walled carbon nanotubes (CNTs), ammonium polyphosphate (APP) and a commercial multifunctional epoxy oligomer (MEO) as chain extender were prepared via melt blending. The results show that the optimal flame retardant properties of PLA5-PBAT5/10A/6C composite containing 6 % CNTs and 10 wt% APP, presented the limited oxygen index reached 28.3 % and exhibited a decrease in peak heat release rate (p HRR) and total heat release (THR) to 368 kJ/m2 and 72 MJ/m2, respectively because of the co-continuous phase, CNTs network and condensed effect of APP. Meanwhile, the construction of co-continuous phases endows PLA5-PBAT5 with better mechanical compared to PLA8-PBAT2 composites. The elongation at break reaches (245.9 %) and notched impact strength (16.5 kJ/m2) of PLA5-PBAT5/10A/6C were higher than the PLA8-PBAT2/10A/6C by 16.0 and 283.7 %. [ABSTRACT FROM AUTHOR]

A series of poly(lactide)/poly(butylene adipate- co -terephthalate) (PLA/PBAT) composites containing different types of multi-walled carbon nanotubes (CNTs) such as hydroxyl and carboxyl-functionalized CNTs were fabricated using the melt blending method. The multifunctional epoxy oligomer (ADR) was selected as a chain extender in order to enhance the compatibility between PBAT and PLA. It was revealed that the addition of ADR could induce CNTs-OH to locate at the PLA/PBAT interface. But the inhibition effect of CNTs-COOH on chain extension reaction in PLA/PBAT blend system led to a decrease in the interaction force between PLA and PBAT owing to the high efficiency of the reaction between CNTs-COOH and ADR. The ε' of PLA/PBAT/4CNTs-OH composite was greater than that of PLA/PBAT/4CNTs-COOH composite because of the strong interaction between fillers and polymer matrix in PLA/PBAT/4CNTs-OH composite. The PLA/PBAT/4CNTs-OH composite showed a high ε' (24.9) and a low tan δ (0.23), respectively. The adjacent CNTs-OH could act as assemble microcapacitors electrodes and the polymer acted as a dielectric to, which greatly increased the interfacial polarization. The PLA/PBAT/4CNTs-OH composite has excellent mechanical and dielectric properties. [ABSTRACT FROM AUTHOR]

The sandwich-structured polyacrylate composite films containing carbon nanotubes (CNTs) and magnetic fillers (Ni or Fe 3 O 4) were prepared by spray coating and LBL-casting. CNTs were uniformly distributed in polyacrylate (PEA) matrix to prepare middle layer and magnetic fillers exhibited good distribution in PEA matrix as outer layer to reduce the secondary electromagnetic radiation pollution. The average electromagnetic interference shielding effectiveness (EMI SE) owns the highest value of 38.2 dB in 6-Fe 3 O 4 /MWCNT/6-Fe 3 O 4 film, and the absorption coefficient (A) of the film account for about 0.56. The results indicated that this film shows absorption-dominated EMI shielding properties. It is mainly attributed to sandwich structure of the composite film, synergistic electric/magnetic losses and polarization relaxation loss to further attenuate electromagnetic wave. The microwave can undergo a unique "absorb-reflect-reabsorb" process. Therefore, polyacrylate composite films with low reflection and high EMI shielding can be used in small-scale and sophisticated electronic devices. • The polyacrylate films exhibit high absorption and low reflection EMI performance. • The EMI SE owns the highest value of 38.2 dB when the Fe 3 O 4 content is 6 wt%. • The absorption coefficient of 6-Fe 3 O 4 /MWCNT/6-Fe 3 O 4 film is about 0.56. • Adding hybrid fillers can effectively alleviate the impedance mismatch. • Constructing sandwich structure extends the electromagnetic wave transmission path. [ABSTRACT FROM AUTHOR]

Highlights • SR8/POE2-MILs and SR6/POE4-MILs show sea-island and co-continuous structure respectively. • The SR8/POE2-MILs possesses high dielectric permittivity and low loss. • MILs distributed in the dispersed phase POE can inhibit conductive loss and ionic polarization. Abstract Silicone rubber (SR)/polyolefin elastomer (POE) blends containing 1-vinyl-3-ethylimidazolium bromide ionic liquids (ILs) modified multi-walled carbon nanotubes (MWCNTs) were prepared by melt-blending and hot pressing. SR8/POE2-MILs (MWCNTs modified by ILs) composites show sea-island structure. The viscosity and volume fraction of POE-MILs localized in the POE domains could induce phase inversion and form co-continuous structure in SR6/POE4-MILs composites. The dielectric permittivity and loss of the composites increased significantly with increasing MILs content because space charge carriers aggregated at the interface between MILs and polymer and formed interfacial polarization. The SR8/POE2-MILs composites possess high dielectric permittivity and low loss because MILs distributed in the dispersed phase POE can inhibit conductive loss and ionic polarization. [ABSTRACT FROM AUTHOR]

The interfacial compatibilization and dispersion of carbon nanotubes (CNTs) in incompatible poly(lactic acid)/poly(butylene terephthalate adipate) (PLA/PBAT) composites are key points for evaluating the performance of the composites. To address this, a novel compatibilizer, sulfonate imidazolium polyurethane (IPU) containing PLA and poly(1,4-butylene adipate) segments modified CNTs, employed in conjunction with multi-component epoxy chain extender (ADR) to toughen synergistically PLA/PBAT composites. The thermal stability, rheological behavior, morphology, and mechanical properties of PLA/PBAT composites were performed by TGA, DSC, dynamic rheometer, SEM, tensile, and notched Izod impact measure. Moreover, the elongation at break and notched Izod impact strength of PLA5/PBAT5/4C/0.4I composites achieved 341 % and 61.8 kJ/m2 respectively, whose tensile strength was 33.7 MPa. The interfacial compatibilization and adhesion were enhanced because of the interface reaction catalyzed by IPU and the refined co-continuous phase structure. The CNTs non-covalently modified by IPU that bridged at the PBAT phase and interface transferred the stress into the matrix, prevented the development of microcracks, and absorbed impact fracture energy in the form of pull-out of the matrix, inducing shear yielding and plastic deformation. This new type of compatibilizer with modified CNTs is of great significance for realizing the high performance of PLA/PBAT composites. [ABSTRACT FROM AUTHOR]

The interfacial compatibilization and dispersion of carbon nanotubes (CNTs) in incompatible poly(lactic acid)/poly(butylene terephthalate adipate) (PLA/PBAT) composites are key points for evaluating the performance of the composites. To address this, a novel compatibilizer, sulfonate imidazolium polyurethane (IPU) containing PLA and poly(1,4-butylene adipate) segments modified CNTs, employed in conjunction with multi-component epoxy chain extender (ADR) to toughen synergistically PLA/PBAT composites. The thermal stability, rheological behavior, morphology, and mechanical properties of PLA/PBAT composites were performed by TGA, DSC, dynamic rheometer, SEM, tensile, and notched Izod impact measure. Moreover, the elongation at break and notched Izod impact strength of PLA5/PBAT5/4C/0.4I composites achieved 341 % and 61.8 kJ/m2 respectively, whose tensile strength was 33.7 MPa. The interfacial compatibilization and adhesion were enhanced because of the interface reaction catalyzed by IPU and the refined co-continuous phase structure. The CNTs non-covalently modified by IPU that bridged at the PBAT phase and interface transferred the stress into the matrix, prevented the development of microcracks, and absorbed impact fracture energy in the form of pull-out of the matrix, inducing shear yielding and plastic deformation. This new type of compatibilizer with modified CNTs is of great significance for realizing the high performance of PLA/PBAT composites. [ABSTRACT FROM AUTHOR]

[Display omitted] • The EMI SE of PU/10Ni@CNTs/10CNTs fabric reaches 77.2 dB. • The synergy of electrical, dielectric, and magnetic loss caused excellent EMI SE. • CNTs and Ni@CNTs weave into a stable electrical and magnetic permeability network. Waterborne polyurethane (WPU) fabrics containing multiwalled carbon nanotubes (CNTs) and Ni coated multiwalled carbon nanotubes (Ni@CNTs) were successfully fabricated through emulsion mixing and drop-coating method. Carbon-based nanofillers were distributed in the conformal WPU matrix and fabric substrate, and intertwined with each other to form electric/magnetic network. The electromagnetic interference shielding effectiveness (EMI SE) of PU/10Ni@CNTs/10CNTs fabric reaches 77.2 dB, batter than that PU/20CNTs fabrics due to the synergistic effect of electrical, dielectric, and magnetic loss. [ABSTRACT FROM AUTHOR]

Synergistically improved mechanical and dielectric properties of poly(lactic acid)/ethylene–methyl acrylate–glycidyl methacrylate random terpolymer (PLA/EMA-GMA) based nanocomposites containing ionic liquids (ILs) and multi-walled carbon nanotubes (MWCNTs) can be related to the morphological evolution and interface properties of the composites. ILs can catalyze the reaction between PLA and EMA-GMA and MWCNTs can induce morphology transformation from sea-island structure to quasi-cocontinuous structure. The rheological tests show that the G′ of samples significantly increased and G″ decreased with increasing the MWCNTs content. This indicates that a crosslink structure at PLA/EMA-GMA interface and a solid network structure of EMA-GMA/MWCNTs with quasi-cocontinuous morphology were formed by incorporation of ILs. Morphology transformation and interfacial enhanced compatibilization significantly improved the mechanical and dielectric properties of composites owing to the formation of MWCNTs network in EMA-GMA phase and interfacial crosslinked structure. Image 1 [ABSTRACT FROM AUTHOR]

Poly (l -lactide) (PLLA) based ternary nanocomposites were fabricated by introducing in situ crosslinked poly(ethylene glycol) diacrylate (CPEGDA) as the rubbery toughening modifier and multiwall carbon nanotubes (MWCNTs) as the conductive fillers. Due to the incorporation of MWCNTs, the domain size of CPEGDA became smaller and MWCNTs were selectively distributed in PLLA continuous phase, facilitating to balance the stiffness and toughness. Rheological investigation showed that the formation of a double network of CPEGDA and MWCNTs resulted in constrained molecular mobility, thus greatly increasing the modulus and viscosity at low frequencies and long-time relaxation strength. The low percolation threshold of MWCNTs in electrical conductivity was found to be 0.19 vol% and the electromagnetic interference shielding effectiveness (EMI SE) of 26.4 dB was achieved with incorporating 2.4 vol% of MWCNTs. This work could provide a novel way to fabricate PLLA based eco-friendly nanocomposites with simultaneous superior mechanical properties and excellent EMI shielding performance. [ABSTRACT FROM AUTHOR]

• SR8/POE2-MILs and SR6/POE4-MILs show sea-island and co-continuous structure respectively. • SR6/POE4/MILs shows high EMI shielding properties due to high electrical conductivity. • The tensile strength and the elongation at break of SR6/POE4/7MILs could reach 6.4 Mpa and 182.7% respectively. Silicone rubber (SR)/polyolefin elastomer (POE) blends containing 1-vinyl-3-ethylimidazolium bromide ionic liquids (ILs) modified multi-walled carbon nanotubes (MWCNTs) were prepared by melt blending and hot pressing. ILs can improve the dispersion of MWCNTs through cation-π interactions and MILs were localized within the SR phase. SR8/POE2/MILs and SR6/POE4/MILs nanocomposites exhibit sea-island and co-continuous structures, respectively. The electromagnetic interference (EMI) shielding performance of the composites increased significantly with the increase of MILs content because MILs can form more conductive network and enhance the leakage current. Moreover, the shielding effectiveness (SE) of the co-continuous structured SR6/POE4/MILs composites is higher than that of sea-island structured SR8/POE2/MILs composites due to the uniform dispersion of MILs in co-continuous structure, which resulted in enhanced electrical conductivity. SR6/POE4/7MILs composite exhibited a tensile strength of 6.4 MPa. The present study provides a novel and efficient route to prepare flexible nanocomposites with enhanced EMI shielding and superior mechanical performance. [ABSTRACT FROM AUTHOR]