Synthesis of EP‐POSS mixture and the properties of EP‐POSS/epoxy,SiO2/epoxy,and SiO2/EP‐POSS/epoxy nanocomposite

The hybrid material of EP‐POSS mixture was synthesized by the hydrolysis and condensation of (γ‐glycidoxypropyl) trimethoxysilane. A series of binary systems of EP‐POSS/epoxy blends, epoxy resin modified by silica nanoparticles (SiO₂/epoxy), and ternary system of SiO₂/EP‐POSS/epoxy nanocomposite were prepared. The dispersion of SiO₂ in the matrices was evidenced by transmission electron micrograph, and the mechanical properties, that is, flexural strength, flexural modulus, and impact strength were examined for EP‐POSS/epoxy blends, SiO₂/epoxy, and SiO₂/EP‐POSS/epoxy, respectively. The fractured surface of the impact samples was observed by scanning electron micrograph. Thermogravimetry analysis were applied to investigate the different thermal stabilities of the binary system and ternary system by introducing EP‐POSS and SiO₂ to epoxy resin. The results showed that the impact strength, flexural strength, and modulus of the SiO₂/EP‐POSS/epoxy system increased around by 57.9, 14.1, and 44.0% compared with the pure epoxy resin, T_i, T_max and the residues of the ternary system were 387°C, 426°C, and 25.2%, increased remarkably by 20°C, 11°C and 101.6% in contrast to the pure epoxy resin, which was also higher than the binary systems. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 810‐819, 2013     

Synthesis of PS‐g‐POSS hybrid graft copolymer by click coupling via ”graft onto” strategy

Polystyrene (PS)‐incorporated polyhedral oligomeric silsesquioxanes (POSS) organic–inorganic hybrid graft copolymer could be achieved by click coupling reaction between alkyne groups in POSS and azido groups in PS via “graft onto” strategy. Alkyne‐functionalized POSS was synthesized via thiol‐ene facile click reaction and subsequent amidation reaction with very high yield. Azido‐multifunctionalized PS could be synthesized by chloromethylation and subsequent azido reaction. The chemical structures of PS‐(CH₂Cl)_m, PS‐(CH₂N₃)_m, and PS‐g‐POSS were determined by Fourier transform infrared and ¹H NMR characterization. PS‐g‐POSS presented a better hydrophobic property with contact angle of 113° than that of PS (85°). And PS‐g‐POSS with ≤5% of grafting degree had lower glass transition temperature (T_g) than that of PS and then it increased up to 112°C with grafting degree. An obvious aggregation of POSS phase with 10–80 nm in size was formed in PS‐g‐POSS matrix. In addition, 5 wt % of PS‐g‐POSS was added to general purpose polystyrene (GPPS) to remarkably improve its tensile strength from 45 to 57 MPa. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis,Morphology and Viscoelastic Properties of Epoxy/Polyhedral Oligomeric Silsesquioxane (POSS) and Epoxy/Cyanate Ester/POSS Nanocomposites

TriSilanolPhenyl-polyhedral oligomeric silsesquioxane (POSS-1) (C₄₂H₃₈O₁₂Si₇), 1–15 wt%, was incorporated into aliphatic epoxy resin (Clearstrem Products, Inc.) with aliphatic diamine curing agents and cured. This epoxy resin was also blended with an equal weight (50/50 w/w) of aromatic cyanate ester resin, Lonza’s PT-15, and 1–15 wt% of POSS-1 and cured. These composites were characterized by FT-IR, X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (X-EDS), dynamic mechanical thermal analysis (DMTA) and three-point bending flexural tests. XRD and X-EDS measurements were consistant with partial molecular dispersion of the POSS units in the continuous matrix phase, together with POSS aggregates. TEM and SEM show that POSS-1-enriched nanoparticles are present in the matrix resins of both the epoxy/POSS and epoxy/cyanate ester/POSS-1 composites. The storage bending moduli, E′, in the rubbery region and the glass transition temperatures, T_g, of epoxy and epoxy/cyanate ester 1-5% POSS-1 composites are higher than those of the reference resins. Small amounts (≤5 wt%) of POSS-1 improved E′ and T_g of both systems and raised flexural strengths and moduli.     

Synthesis and characterization of poly(aminobismaleimide)s obtained from solvent‐free mixtures

A series of eight poly(aminobismaleimide)s containing aromatic units have been synthesized from a one‐step nucleophilic addition reaction between diamine and bismaleimide, without exogeneous solvent, to provide encapsulant withstanding high temperature suitable for power electronics. To have a homogeneous medium at room temperature, the solid aromatic diamines are first mixed with different liquid aliphatic ones, and then mixed with bismaleimide. The syntheses were then carried out at 175 °C for 15 min. Thus, according to their composition, these obtained thermosetting resins are characterized by a relaxation temperature between 98 and 190 °C and a coefficient of thermal expansion between 20 and 150 ppm/K. All material surfaces are hydrophobic and their moisture uptake is lower than 2–3 wt %. Finally, as expected, the substitution of a part of the aliphatic diamine by an aromatic one improves the thermal stability under air atmosphere of the resulting materials (T_d = 280–300 °C increased to T_d = 315–340 °C). Their use as power module encapsulant can therefore be considered. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46105.     

Influence of polyhedral oligomeric silsesquioxanes on thermal and mechanical properties of polycarbonate/POSS hybrid composites

Two types of silsesquioxanes were synthesized by hydrolytic condensation reaction, and then were incorporated into polycarbonate (PC) matrix by melt blending to prepare PC/POSS hybrid composites. The study of morphology of the composites showed that octaphenylsilsesquioxane (PH‐POSS) exhibited partial compatibility with PC matrix, while 3‐glycidyloxypropylsilsesquioxane (EP‐POSS) could react with phenolic hydroxyl groups of matrix. Thermal and mechanical properties were studied by DSC, TGA, and DMA. The result showed that the incorporation of POSS not only improved thermal stabilities of PC composites, but also retarded their thermal degradation. Si O fractions left during POSS degradations were the key factor governing the formation of a gel network layer on the exterior surface. This layer possessed more compact structures, higher thermal stabilities, and some thermal insulation. In addition, percentage residues at 700°C (C₇₀₀) significantly increased from 10.8 to 15.5–22.8% in air. The storage modulus of two series of composites was slightly improved up to 90°C; furthermore, the temperature range of the rubbery state of them shifted to high temperature. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers     

Isothermal crystallization of HDPE/octamethyl polyhedral oligomeric silsesquioxane nanocomposites: Role of POSS as a nanofiller

The isothermal crystallization of HDPE/POSS (polyhedral oligomeric silsesquioxane) nanocomposites (POSS content varying from 0.25 to 10 wt %) was studied using differential scanning calorimetry (DSC) technique. The Avrami model could successfully describe the isothermal crystallization behavior of the nanocomposites. The value of Avrami exponent (n) varies between 2 and 2.5 for all the compositions studied. For a given composition, the values vary with crystallization temperature and in general increased with POSS content up to 1 wt % POSS content and decreased thereafter. The presence of POSS was found to increase the rate of crystallization, which manifested itself in the increased value of the Avrami rate constant (K) and reduced value of crystallization half‐time (t_1/2). The rate of crystallization peaked at 1 wt % POSS content and was almost constant at higher POSS loadings. X‐ray diffraction studies revealed that POSS exists as nanocrystals in HDPE matrix while some POSS gets dispersed at molecular level too. It is observed that only the POSS dispersed at molecular level acts as a nucleating agent while the POSS nanocrystals do not affect the crystallization process. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Preparation and properties of bio‐based epoxy montomorillonite nanocomposites derived from polyglycerol polyglycidyl ether and ε‐polylysine

Glycerol polyglycidyl ether (GPE) and polyglycerol polyglycidyl ether (PGPE) were cured with ε‐poly(L ‐lysine) (PL) using epoxy/amine ratios of 1 : 1 and 2 : 1 to create bio‐based epoxy cross‐linked resins. When PGPE was used as an epoxy resin and the epoxy/amine ratio was 1 : 1, the cured neat resin showed the greatest glass transition temperature (T_g), as measured by differential scanning calorimetry. Next, the mixture of PGPE, PL, and montomorillonite (MMT) at an epoxy/amine ratio of 1 : 1 in water was dried and cured finally at 110°C to create PGPE‐PL/MMT composites. The X‐ray diffraction and transmission electron microscopy measurements revealed that the composites with MMT content 7–15 wt % were exfoliated nanocomposites and the composite with MMT content 20 wt % was an intercalated nanocomposite. The T_g and storage modulus at 50–100°C for the PGPE‐PL/MMT composites measured by DMA increased with increasing MMT content until 15 wt % and decreased at 20 wt %. The tensile strength and modulus of the PGPE‐PL/MMT composites (MMT content 15 wt %: 42 and 5300 MPa) were much greater than those of the cured PGPE‐PL resin (4 and 6 MPa). Aerobic biodegradability of the PGPE‐PL in an aqueous medium was ～ 4% after 90 days, and the PGPE‐PL/MMT nanocomposites with MMT content 7–15 wt % showed lower biodegradability. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Effect of trisilanolphenyl‐POSS on rheological,mechanical, and flame‐retardant properties of poly(ethylene terephthalate)/cyclotriphosphazene systems

Poly(ethylene terephthalate) (PET) chips were coated by trisilanolphenyl–polyhedral oligomeric silsesquioxane (T‐POSS) and hexakis (para‐allyloxyphenoxy) cyclotriphosphazene (PACP) using the predispersed solution method, and PET/PACP/T‐POSS hybrids were further prepared by the melt‐blending method. The influence of T‐POSS on the rheological, thermal, and mechanical properties and flame retardancy of PET/PACP composites were discussed. The results suggest that T‐POSS was homogeneously dispersed in the PET matrix, which reduced the negative effects on polymer rheology and mechanical properties. For the PET/4%PACP/1%T‐POSS sample, the tensile strength at break and T_g increased from 29.67 MPa and 81.7 °C (PET/5%PACP) to 34.8 MPa and 85.8 °C, respectively, but the sample also self‐extinguished within 2 s, and the heat release capacity was reduced by 27.9% in comparison with that of neat PET.© 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45912.     

Catalytic effect of 2,2′‐diallyl bisphenol A on thermal curing of cyanate esters

Cyanate esters are a class of thermal resistant polymers widely used as thermal resistant and electrical insulating materials for electric devices and structural composite applications. In this article, the effect of 2,2′‐diallyl bisphenol A (DBA) on catalyzing the thermal curing of cyanate ester resins was studied. The curing behavior, thermal resistance, and thermal mechanical properties of these DBA catalyzed cyanate ester resins were characterized. The results show that DBA is especially suitable for catalyzing the polymerization of the novolac cyanate ester resin (HF‐5), as it acts as both the curing catalyst through depressing the exothermic peak temperature (T_exo) by nearly 100°C and the toughening agent of the novolac cyanate ester resin by slightly reducing the elastic modulus at the glassy state. The thermogravimetric analysis and dynamic mechanical thermal analysis show that the 5 wt % DBA‐catalyzed novolac cyanate ester resin exhibits good thermal resistance with T_d⁵ of 410°C and the char yield at 900°C of 58% and can retain its mechanical strength up to 250°C. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1775–1786, 2006     

Phase-separated structures of random methacrylate copolymers with pendant POSS moieties

The phase separation of random methacrylate copolymers with the pendant polyhedral oligomeric silsesquioxanes (POSS) moieties was studied. For the random copolymers of the phenyl-substituted POSS methacrylate (PhPOSSMA) and butyl methacrylate (BMA), the layer-like phase-separated structures were obtained from the copolymers with over circa 20 wt % of PhPOSSMA after thermal annealing in the bulk. The copolymers with larger PhPOSSMA content over 40 wt % showed periodic phase-separated structure with the periodic length ranging from 9.0 to 5.1 nm depending on the composition. The phase separation did not occur by solvent annealing in the bulk. On the other hand, no phase-separated structure was formed from the random copolymer with circa 50 wt % of isobutyl-substituted POSSMA (i-BuPOSSMA) and BMA after thermal annealing. In addition, the phase separation did not occur for both of the random copolymers of PhPOSSMA and i-BuPOSSMA with methyl methacrylate. The resulting phase-separated structures were well characterized by using wide-angle X-ray scattering, small-angle X-ray scattering, and transmission electron microscopy image. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47246.     

Low dielectric and high thermal conductivity epoxy nanocomposites filled with NH2‐POSS/n‐BN hybrid fillers

Hybrid fillers of mono‐amine polyhedral oligomeric silsesquioxane/nanosized boron nitride (NH₂‐POSS/n‐BN) were performed to fabricate NH₂‐POSS/n‐BN/epoxy nanocomposites. Results revealed that the dielectric constant and dielectric loss values were decreased with the increasing addition of NH₂‐POSS obviously, but increased with the increasing addition of BN fillers. For a given loading of NH₂‐POSS (5 wt %), the thermal conductivities of NH₂‐POSS/n‐BN/epoxy nanocomposites were improved with the increasing addition of n‐BN fillers, and the thermal conductivity of the nanocomposites was 1.28 W/mK with 20 wt % n‐BN fillers. Meantime, the thermal stability of the NH₂‐POSS/n‐BN/epoxy nanocomposites was also increased with the increasing addition of n‐BN fillers. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41951.     

Morphology and rheological behaviors of poly(ethylene terephthalate) nanocomposites containing polyhedral oligomeric silsesquioxanes

Poly(ethylene terephthalate) (PET)/polyhedral oligomeric silsesquioxane (POSS) nanocomposites were prepared by in situ polymerization. Light scattering measurement suggested that there is significant change in molecular weight arising from gel formation by chemical crosslinking during polymerization. The thermal decomposition temperatures of the composites measured at 5 wt % weight loss were 5–10°C higher than that of PET. There is no significant change in other thermal properties. Scanning electron microscopy observations suggest that there is obvious phase separation in PET/POSS composites, composites containing 1 wt % of disilanolisobutyl and trisilanolisobytyl‐POSS show fine dispersions of POSS (30–40 nm in diameter), which arise from strong interfacial interactions between POSS and PET during polymerization. The viscosity of the composites increased with the addition of POSS. The observation of a plateau region of composites containing 1 wt % of POSS in the plot of log G′ vs. log G″ indicates strong interfacial interactions between POSS and PET. Sixty‐three percent and 41% increase in tensile strength and 300 and 380% increase in modulus were achieved in the composites containing 1 wt % of disilanol‐ and trisilanol‐POSS, respectively. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Epoxy/POSS organic–inorganic hybrids: Viscoelastic,mechanical properties and micromorphologies

A series of epoxy resin (EP)/octa(aminpropyl)silsesquioxane (POSS‐NH₂) organic–inorganic hybrid composites (EP/POSS‐NH₂ 100/0, 95/5, 90/10, and 80/20 wt/wt) were prepared by melt casting and then curing. Viscoelastic and mechanical properties of these composites were studied by dynamic mechanical analysis and mechanical testing, respectively. Scanning electron microscopy was used to study of the micromorphologies of the composites and to elucidate the toughening mechanisms of POSS‐NH₂. POSS units incorporated into the epoxy network showed good compatibility with the resin matrix. Phase separation was not observed even at high POSS content (20 wt%). Incorporation of POSS macromer into the epoxy network after curing increased the glass transition temperature, slightly narrowed the temperature range widths of the glass transition, and lowered the intensities of their loss moduli peaks of the resultant composites. The glass transition temperature of EP/POSS‐NH₂ composites increased significantly with increasing POSS content at lower POSS content (<10 wt%), while increased slightly at higher POSS content. Both impact and flexural strengths of the hybrids reached their optimum values when 10 wt% content of POSS was introduced. POLYM. COMPOS., 28:175–179, 2007. © 2007 Society of Plastics Engineers.     

Polyhedral oligomeric silsesquioxanes nanoreinforced methacrylate/epoxy hybrids

The aim of this study was to design novel binary and ternary copolymers based on methacrylate and/or epoxy monomers reinforced with 10 wt % mono‐/octafunctional polyhedral oligomeric silsesquioxanes (POSS) compounds bearing one or eight epoxy or methacrylate moieties. The experimental parameters such as temperature and time of reaction, comonomer ratio and the incorporation of various types of POSS that strongly influences the curing behavior, polymerization kinetics, glass transition temperature (T_g), thermostability and morphological structure of the obtained copolymers were investigated through DSC, FTIR, DMA, TGA, and SEM techniques. The obtained results evidenced that the complex kinetic mechanisms of curing reactions for the binary and ternary copolymers ± POSS influence the thermomechanical and morphological properties of the materials. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42912.     

Methacrylate/acrylate terminated derivatives of diglycidyl hexahydrophthalate: Synthesis,structural, and thermal characterization

Mono‐ or di(meth)acrylate‐terminated derivatives of diglycidyl hexahydrophthalate (ER) were prepared by reacting 1 : 1 or 1 : 2M ratio of ER and methacrylic acid or acrylic acid. These vinyl ester (VE) resins were characterized by determining epoxy equivalent weight, acid number, and molecular weight by gel permeation chromatography. Structural characterization was done by FTIR and ¹H NMR spectroscopy. In the ¹H NMR spectra of acrylate‐terminated VE resins, three proton resonance signals were observed in the region 5.8–6.4 ppm due to vinyl group while in methacrylate‐terminated VE resins only two proton resonance signals due to vinylidene protons were observed at 5.6–6.1 ppm. The Brookfield viscosity (room temperature (25 ± 2)°C) of these resins diluted with varying amounts of MMA was determined at 20 rpm. Curing behavior was monitored by determination of gel time and differential scanning calorimetry. An exothermic transition was observed in the DSC scans in the temperature range of (81–150)°C. Isothermal curing of MMA‐diluted VE resins containing AIBN as an initiator was done at 60°C for 2 h in N₂ atmosphere, and then heating for another 2 h in static air atmosphere. Thermal stability of isothermally cured resins in N₂ atmosphere was evaluated by thermogravimetric analysis. All cured resins decomposed above 310°C in single step. Thermal stability of the cured resins having acrylate end caps was marginally higher than the resins having methacrylate end groups. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Nonisothermal decomposition kinetics of nylon 1010/POSS composites

The thermal stability of nylon 1010/polyhedral oligomeric silsesquioxane (POSS) composites prepared by melt blending was investigated with thermogravimetric analysis. The octavinyl POSS (vPOSS) and epoxycyclohexyl POSS (ePOSS) were used, and it was found that nylon/vPOSS composites have higher integral procedure decomposition temperature and char yield at 800°C than nylon/ePOSS composites. The Doyle–Ozawa (model‐free) and Friedman (model‐fitting) methods were used to characterize the nonisothermal decomposition kinetics of nylon 1010 and its composites. The activation energy (E_a), reaction order (n), and the natural logarithm of frequency factor of nylon 1010 were 267 kJ/mol, 1.0, and 47 min^?1, respectively, in nitrogen. After the addition of POSS, the E_a of nylon 1010 considerably increased, whereas n had less change. The E_a steadily increased with increasing conversion and with increasing heating rate. The lifetime of nylon 1010 and its composites decreased with increasing temperature. At a given temperature, POSS significantly prolonged the lifetime of nylon 1010. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Degradation kinetic of epoxy nanocomposites containing different percentage of epoxycyclohexyl—POSS

In this study, epoxy nanocomposites containing 0.5, 1, 2, and 5% (m/m) of epoxycyclohexyl—POSS were prepared by mechanical mixture. The samples were characterized by gel content, thermogravimetric analysis (TGA), transmission electron microscopy, and scanning electron microscopy (SEM). TGA analysis was carried out at different heating rates (5, 10, 20, and 40°C min⁻¹) aiming to evaluate the decomposition by Avrami, Flynn‐Wall‐Ozawa and Criado kinetic models. It was constated an increase in the gel fraction and dispersion of the nanocages only for the sample containing 5% POSS. The degradation study showed two distinct stages of weight loss and only for the first stage a shift in the temperature up POSS incorporation was observed. The Avrami kinetic parameters showed that the incorporation of POSS does not affect the degradation rate constant; however, there is an increase in the time required for the degradation reaction occurs. Also, it was observed an increase in the activation energy values for the sample containing 5% (m/m) of POSS. The degradation kinetic mechanisms in presence of POSS was changed from deceleratory mode (F₁) for diffusion (D_n) in the range corresponded to the second stage of weight loss. SEM analysis showed that the morphology of the epoxy resin was modified by the POSS presence, and for 5% (m/m) of POSS was constated a more homogeneous morphology in relation to other samples. © 2012 Society of Plastics Engineers     

Improvement of thermal ageing and transparency of methacrylate based poly(siloxane–silsesquioxane) for optoelectronic application

Trisilanolphenyl–polyhedral oligosilsesquioxane (trisilanolphenyl–POSS) structure is introduced into a polysiloxane network in an attempt to produce thermally stable material with improved transparency. A series of organic–inorganic resins comprised of diphenylsilanediol, 3‐methacryloxypropyl trimethoxysilane, and varying content of trisilanolphenyl–POSS were copolymerized through condensation followed by curing using phenyltris(hydrogendimethylsiloxy)silane as curing agent. Fourier transform infrared spectroscopy (FTIR), proton‐nuclear magnetic resonance spectroscopy (¹H‐NMR), and silicon‐nuclear magnetic resonance spectroscopy (²⁹Si‐NMR) were used to confirm the synthesized product. Excellent thermal stability, improved glass transition temperature (T_g), and lower coefficient of thermal expansion with the increasing POSS content were observed from thermomechanical analysis. Its extreme thermal degradation stability was attributable to the crosslinked network as well as the heavily substituted aromatic ring present in the system. Steric hindrance effect is noticeable beyond 5.66 mol % trisilanolphenyl–POSS content. Incorporation of POSS substituent in methacrylate‐based polysiloxane give excellent transparency and improved thermal discoloration resistance as deduced from UV/vis Spectrophotometer, making it a potential material to be used in optoelectronics. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45285.     

Novel elastomer‐dumbbell functionalized POSS composites: Thermomechanical and Morphological Properties

Nanocomposites consisting of poly(styrene‐b‐butadiene‐b‐styrene) (SBS) and polyhedral oligomeric silsesquioxanes (POSS) were prepared using a solvent dispersion method. Dumbbell‐shaped POSS fillers were prepared using diacyl chlorides to bridge the POSS molecules. Infrared spectroscopy confirmed functionalization. Scanning electron microscopy revealed an increase in filler aggregation with concentration, with preferential phase selectivity. Polydispersity increased with filler concentration while d spacing was influenced by phase selectivity and domain‐filler compatibility. Functionalized POSS improved thermal stability by imparting restrictions of SBS chain motions. Tensile stress–strain analysis revealed an increase in modulus, yield strength, and strain hardening with filler concentration, while creep deformation decreased and permanent strain increased with POSS content. Storage modulus, loss modulus, and glass transition temperature increased with filler content due to effective SBS–POSS interaction. Nanocomposite properties were influenced by filler concentration, the phase of the filler was dispersed throughout and the length of the alkyl “barbell” on the dumbbell‐shaped POSS. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

High-Performance Low-k Poly(dicyclopentadiene) Nanocomposites as Achieved via Reactive Blending with Norbornene-Functionalized Larger POSS

Low dielectric constant (k) polymers with excellent comprehensive properties are useful materials in the microelectronics industry as matrix resins or encapsulation layers. With the inherent low polarization, high reactivity, good processability, and low cost, poly(dicyclopentadiene) (PDCPD) has received considerable attention as low-k materials. However, its practical application is limited by the relatively high thermal expansion and k value. Herein, three norbornene-functionalized polyhedral oligomeric silsesquioxanes (POSSs) with T₈, T₁₀, and T₁₂ polyhedral cores are synthesized and employed for enhancing the dielectric and comprehensive properties of PDCPD via reactive blending. The results show that these POSSs have good compatibility with PDCPD matrix and nano-dispersed POSSs particles could be obtained. As a result, the materials’ properties can be largely enhanced by varying the POSS content and POSS size. Especially, PT₁₂N₁₂-40 (40 wt% of T₁₂N₁₂) shows the lowest k value (2.1) and coefficient of thermal expansion (63.4 ppm°C⁻¹), highest glass transition temperature (202.5 °C), yield strength (78.0 MPa), and elastic modulus (2.36 GPa), along with excellent hydrophobicity. This study highlights a useful strategy to fabricate high-performance low-k polymer nanocomposites by using larger POSS and reactive blending, which provides useful materials for the future microelectronic industry and high frequency communication.