The Recent Advances of Polymer-POSS Nanocomposites With Low Dielectric Constant

This study provides a comprehensive overview of the preparation methods for polyhedral oligomeric silsesquioxane (POSS) monomers and polymer/POSS nanocomposites. It focuses on the latest advancements in using POSS to design polymer nanocomposites with reduced dielectric constants. The study emphasizes exploring the potential of POSS, either alone or in combination with other materials, to decrease the dielectric constant and dielectric loss of various polymers, including polyimides, bismaleimide resins, poly(aryl ether)s, polybenzoxazines, benzocyclobutene resins, polyolefins, cyanate ester resins, and epoxy resins. In addition, the research investigates the impact of incorporating POSS on improving the thermal properties, mechanical properties, surface properties, and other aspects of these polymers. The entire study is divided into two parts, discussing systematically the role of POSS in reducing dielectric constants during the preparation of POSS composites using both physical blending and chemical synthesis methods. The goal of this research is to provide valuable strategies for designing a new generation of low dielectric constant materials suitable for large-scale integrated circuits in the semiconductor materials domain.

Synthesis and microwave absorption studies on 2D graphitic carbon nitride loaded polyaniline/polyvinyl alcohol nanocomposites

A light weight electromagnetic interference (EMI) shielding and microwave absorbing composite films has been developed by loading varying weight content of graphitic carbon nitride (g-C3N4) nanosheets and polyaniline (PANI) into polyvinyl alcohol (PVA) matrix. The prepared PVA/PANI/g-C3N4 (1%, 3%, 5%) composites has been subjected to FTIR, X-Ray powder diffraction, SEM, Thermal studies, Dielectric studies and electromagnetic shielding effectiveness (EMI SE) analysis. The PVA/PANI/g-C3N4 (1%, 3%, 5%) composites was discovered to have improved electrical conductivity, dielectric loss, and dielectric constant. It is observed from the SEM images that the sheet layers of g-C3N4 are wrapped by the polymer matrix and the morphology to PVA/PANI composite in the g-C3N4 indicates homogeneous blending of PVA/PANI without any phase separation and has porous in it. The PANI/g-C3N4 fractured surfaces present are smooth but irregular in appearance indicating good compatibility between the PVA and PANI matrices. The dielectric properties was found to increase on increasing the concentration of the g-C3N4 nanofiller and reached a maximum of 9.8 × 106 at 1 MHz for 3% g-C3N4 in PVA/PANI. The incorporation of g-C3N4 into PVA/PANI enhanced the conductivity and the 5% g-C3N4 loaded composite film exhibited a conductivity value of 0.043 S/cm at 1 MHz. The PVA/PANI/g-C3N4 (1%, 3%, 5%) composites exhibited potential EMI SE values ranging from 24 to 35 dB at 8.6 GHz and from 42 to 63 dB at 12.4 GHz, for instance the PVA/PANI/g-C3N4 5% composite showed highest value of 63 dB at 12.4 GHz. The PVA/PANI/g-C3N4 5% exhibits the maximum highest reflection loss 8 GHz–12 GHz in which the higher absorption of −36 dB is observed at 10.3 GHz of the X-band region.

High Thermal Resistance of Epoxy/Cyanate Ester Hybrids Incorporating an Inorganic Double-Decker-Shaped Polyhedral Silsesquioxane Nanomaterial

In this study, we prepared a difunctionalized cyanate ester double-decker silsesquioxane (DDSQ-OCN) cage with a char yield and thermal decomposition temperature (T_d) which were both much higher than those of a typical bisphenol A dicyanate ester (BADCy, without the DDSQ cage) after thermal polymerization. Here, the inorganic DDSQ nanomaterial improved the thermal behavior through a nano-reinforcement effect. Blending the inorganic DDSQ-OCN cage into the epoxy resin improved its thermal and mechanical stabilities after the ring-opening polymerization of the epoxy units during thermal polymerization. The enhancement in the physical properties arose from the copolymerization of the epoxy and OCN units to form the organic/inorganic covalently bonded network structure, as well as the hydrogen bonding of the OH groups of the epoxy with the SiOSi moieties of the DDSQ units. For example, the epoxy/DDSQ-OCN = 1/1 hybrid, prepared without Cu(II)-acac as a catalyst, exhibited a glass transition temperature, thermal decomposition temperature (T_d), and char yield (166 °C, 427 °C, and 51.0 wt%, respectively) that were significantly higher than those obtained when applying typical organic curing agents in the epoxy resin. The addition of Cu(II)-acac into the epoxy/BADCy and epoxy/DDSQ-OCN hybrids decreased the thermal stability (as characterized by the values of T_d and the char yields) because the crosslinking density and post-hardening also decreased during thermal polymerization; nevertheless, it accelerated the thermal polymerization to a lower curing peak temperature, which is potentially useful for real applications as epoxy molding compounds.

Development of Prosopis juliflora carbon-reinforced PET bottle waste-based epoxy-blended bio-phenolic benzoxazine composites for advanced applications

An attempt has been made in the present work to develop hybrid blended composites using epoxy resin (PETEP) derived from waste polyethylene terephthalate (PET) bottles and bio-phenolic (cardanol)-based benzoxazine (CBz) reinforced with functionalized bio-carbon (f-PJC) obtained from Prosopis juliflora (PJ) for high performance applications. The molecular structure, thermal properties, thermo-mechanical behaviour, morphology, surface properties, and corrosion resistance of the composites were studied by different analytical methods, and the obtained results are reported. Dynamic mechanical properties such as the storage modulus (2.591 GPa), loss modulus (1.299 GPa) and cross-linking density (5.1 × 10⁷ J mol⁻¹ K⁻¹) were improved in the case of the 5 wt% f-PJC/PETEP–CBz composite compared to those of the PETEP–CBz blended matrix and the f-PJC/PETEP–CBz composites with other weight percentages. Among the studied bio-carbon-reinforced hybrid composites with different weight percentages, the 5 wt% f-PJC/PETEP–CBz composite shows a higher value of char yield (38.37%), with an enhanced glass transition temperature of 285 °C and an improved water contact angle of 111.3°. Results obtained from corrosion studies infer that these hybrid composites exhibit improved corrosion resistance behaviour and effectively protect the surface of mild steel specimens from corrosion. It is concluded that the present work can be considered as an effective method for utilizing waste products and sustainable bio-materials for the development of high performance value-added hybrid composites for thermal and corrosion protection applications.

Schematic representation of development of functionalised Prosopis juliflora carbon (f-PJC) reinforced PET-epoxy resin (PETEP) blended bio-phenolic (cardanol) based benzoxazine (CBz) hybrid composites for high performance applications.

Toughening of POSS-MPS composites with low dielectric constant prepared with structure controllable micro/mesoporous nanoparticles

In this work, we developed a modified calcination and extraction method to obtain controllable micro/mesoporous nanoparticle samples POSS–MPS, which were synthesized through glycidyl polyhedral oligomeric silsesquioxane (G-POSS) grafting with aminopropyl-functionalized mesoporous silica (AP-MPS). The POSS–MPS was introduced into the cyanate ester (CE) matrix to optimize the dielectric properties and enhance the toughness of the POSS–MPS/CE nanocomposite. The structure of the hybrid was characterized by FTIR and SEM. The dispersion properties, mechanical properties, dielectric properties and thermal performance were also studied. The results showed that both the C-POSS–MPS and E-POSS–MPS uniformly distribute in the CE matrix with the content of 0.5–4 wt%. The impact strength increased 52% and 60% separately with 2 wt% C-POSS–MPS and E-POSS–MPS addition respectively. The introduction of E-POSS–MPS particles can significantly decrease the dielectric loss value of the POSS–MPS/CE composites to 0.00498, which is of potential in wave transparent composites and structures.

A promising method to improve the performance of CE composites via combining advantages of POSS and MPS.

Nanostructure of reactive polyhedral oligomeric silsesquioxane-based block copolymer as modifier in an epoxy network

To obtain a novel polyhedral oligomeric silsesquioxane (POSS)-based nanomodifier, copolymerization of methacrylate-POSS (MA-POSS) and glycidyl MA (GMA) was carried out via reversible addition-fragmentation chain transfer process. The as-synthesized poly(glycidyl methacrylate) (PGMA)-b-P(MA-POSS) block copolymers (BCPs) were characterized by proton nuclear magnetic resonance, Fourier transform infrared spectroscopy, and gel permeation chromatography. The introduction of a POSS component improved the thermostability of the BCP. Then, PGMA-b-P(MA-POSS) copolymer was reactively incorporated into 4,4′-methylenebis(2,6-diethylaniline) and the epoxy network. Compared with commercial inert MA-POSS-methyl MA (POSS-MMA) copolymers (15 wt% and 45 wt% POSS, respectively), PGMA-b-P(MA-POSS) can self-assemble in epoxy to micelles with diameters of 20–40 nm. Due to the formation of uniform nanostructures, reactive POSS-modified epoxy composites exhibited higher glass transition temperature and double the rubbery state moduli (87 MPa) than neat epoxy (41 MPa). This work provided an efficient way to fabricate a POSS-based nanocomposite via the introduction of nanomodifier PGMA-b-P(MA-POSS) which can pre-react with reactive monomer.

Design of lamellar structured POSS/BPZ polybenzoxazine nanocomposites as a novel class of ultra low-k dielectric materials

A novel class of lamellar structured polyhedral oligomeric silsesquioxane/bisphenol Z (POSS/BPZ) polybenzoxazine (PBz) nanocomposites was successfully designed by a facile one-step copolymerization technique.

Studies on thermal, mechanical, electrical, and morphological behavior of organoclay-reinforced polybenzoxazine–epoxy nanocomposites

Organoclay-reinforced polybenzoxazine–epoxy nanocomposites were prepared via in situ polymerization and thermal, thermomechanical, mechanical, electrical, and morphological properties were characterized by standard methods. Two types of skeletal-modified benzoxazines namely 1,1-bis(3-methyl-4-hydroxyphenyl)cyclohexane benzoxazine and bis(4-maleimidophenyl) benzoxazine were synthesized by reacting paraformaldehyde and 4,4′-diaminodiphenylmethane with 1,1-bis(3-methyl-4-hydroxyphenyl)cyclohexane and N-(4-hydroxyphenyl)maleimide, respectively. Diglycidyl ether bisphenol A epoxy resin was modified with 5, 10, and 15 wt% of benzoxazines and were cured using 4,4′-diaminodiphenylmethane at appropriate conditions. The occurrence of chemical reaction between benzoxazines and epoxy resin was ascertained by Fourier transform infrared spectra. Epoxy and benzoxazines-modified epoxy systems were further reinforced with 1, 3 and 5 wt% of organically modified montmorillonite (OMMT). Thermal behavior of matrices was characterized by differential scanning calorimetry, thermogravimetric analysis, and dynamic mechanical analysis. Mechanical properties were studied as per ASTM standards. The organoclay (OMMT)-reinforced polybenzoxazine–epoxy nanocomposites exhibited lower values of glass transition temperature and dielectric constant/dielectric loss with enhanced values of thermal stability, char yield, impact strength, and storage modulus than those of neat matrix. The morphology of organoclay-reinforced benzoxazine-modified epoxy matrix was studied by scanning electron microscopy, x-ray diffraction, and transmission electron microscopy analyses.

Polysilsesquioxane-reinforced phosphorous containing bis(4-maleimidophenyl)benzoxazine hybrid nanocomposites

In this study, octa(aminophenyl)silsesquioxane (OAPS), octakis(dimethylsiloxypropylglycidylether) silsesquioxane (OG) and phosphorous skeletal bis(4-maleimidophenyl)benzoxazine were synthesized and characterized. The polyhedral oligomeric silsesquioxane (POSS) derivative (OAPS and OG)-reinforced polybenzoxazine (PBZ) hybrid nanocomposites were prepared by thermal method. The chemical reactions between POSS and PBZ were confirmed by Fourier transform infrared spectroscopy. The effect of the incorporation of POSS derivatives on the properties including thermal, dielectric properties and water absorption behaviour of POSS/PBZ hybrids was analyzed and discussed systematically. The test results indicate that the addition of POSS into PBZ increased the thermal stability and decreased the values of dielectric constant and dielectric loss. The morphology of the POSS-PBZ hybrid nanocomposites was characterized using x-ray diffraction, confocal optical microscopy, scanning electron microscopy, transmission electron microscopy and atomic force microscopy.