Filler Surface Treatment Research Articles

Polybutylene adipate terephthalate (PBAT) composites for thermally conductive, fire retardant, high dielectric applications using BaTiO3 and MWCNTs as fillers

This study provides a comprehensive investigation of the fabrication of novel composite materials by blending polybutylene adipate terephthalate (PBAT) with barium titanate (BaTiO3) and multiwalled carbon nanotube (MWCNT) fillers. Prior to fabricating the composites, the filler surface treatments were tailored to enhance their compatibility with the PBAT matrix. Adipic acid (AA), a monomer for PBAT, was employed on the surface of the BaTiO3 particles, while butanediol (BD) also a monomer of PBAT was used to modify the surface of the MWCNTs to ensure effective interaction with the PBAT chains during the composite fabrication process. The composite samples were produced by melt-blending at 140 °C, followed by injection molding at the same operating temperature for subsequent analysis. The results revealed remarkable improvements in the dielectric constant, thermal conductivity, fire retardancy, and tensile strength of the 40 wt% BaTiO3 and MWCNT-PBAT blends compared to pure PBAT. The incorporation of BaTiO3 additionally contributed to enhanced fire retardancy, mechanical properties, and dielectric properties, making the composite material more resistant to ignition and flame spread, thus rendering it suitable for applications requiring elevated fire safety. In addition, the inclusion of MWCNT improved thermal conductivity, enabling promising and efficient heat dissipation in various applications.

Experimental research on the welding strength of PCBN and cemented carbide materials for cutting tools application

The PCBN tools has extensive applications in machining of various ferrous materials. The welding process is the necessary step to connect the PCBN tool nose and cemented carbide tool body. This paper conducted a series of welding experiments between PCBN and cemented carbide, the effect of filler alloy, surface treatment and heating parameters on the shearing strength has been tested and analyzed. The results showed that the addition of active element In in filler alloy can increase the shearing strength by 19.9%, and the side and bottom surface polishing treatment can increase the shearing strength by 124.1% and 96.8%. The adequate heating temperature and time to ensure full chemical metallurgical reaction is significant to obtain the higher shearing strength. At finally, the optimal welding parameters were used in PCBN tool application to improve the welding strength.

Development Aramid Nanofiber‐ and Pentaerythritol‐Grafted Graphene Nanoplate‐Based High‐Performance Thermally Conductive Composites

AbstractA novel filler surface treatment is employed to produce thermally conductive composites using an aramid nanofiber (ANF) and pentaerythritol (PER) grafted onto the surface of graphite nanoplates (GnP). The resulting composite exhibits exceptional properties, including a high through‐plane thermal conductivity of 4 W mK−1, a high tensile strength of 163.58 MPa, and an improved flame retardancy. When the composite is applicated in central processing unit (CPU), the efficient thermal management performance is achieved with a decreased operating temperature of 12 °C. The ANF/GnP–PERANF composites are promising for enhancing thermal management in electric devices. The manufactured ANF composites will open new avenues for advancing the development of next‐generation thermal management systems.

Preparation of Monotrimethoxylsilylethyl-Terminated Polysiloxane Fluids and Their Application in Thermal Interface Materials.

In this study, α-Trimethylsilylmethyl-ω-dimethylsilyl-terminated polydimethylsiloxane, polydiethylsiloxane and poly[2,2,2-trifluoropropyl(methyl)siloxane] are synthesized using an anion catalyzed nonequilibrium polymerization reaction with trimethylsilylmethyl lithium as the initiator; hexamethylcyclotrisiloxane, hexaethylcyclotrisiloxane or 1,3,5-trimethyl-1,3,5-trifluoropropylcyclotrisiloxane as the monomer; and dimethylchlorosilane as an end-capping agent. Three kinds of α-trimethylsilylmethyl-ω-trimethoxylsilylethyl-terminated polysiloxanes are further prepared by hydrosilylation reaction of α-trimethylsilylmethyl-ω-dimethylsilyl-terminated polysiloxanes with vinyltrimethoxysilane using Karstedt's catalyst. These α-trimethylsilylmethyl-ω-trimethoxylsilylethyl-terminated polysiloxanes are functionalized as in situ surface treatment agents for AlN particles. The effects of the structure of these polysiloxanes on the dispersion of AlN in the polysiloxane matrix and on the heat transfer performance of silicone pastes and silicone rubbers are investigated. A possible mechanism of surface treatment of AlN fillers by these novel silicone fluids is also discussed.

Achieving outstanding mechanical/bonding performances by epoxy nanocomposite as concrete–steel rebar adhesive using silane modification of nano SiO2

Anchoring steel rebar in concrete structures is a common method in the building and construction industry. This research focuses on improving the mechanical/bonding properties of the prepared epoxy nanocomposite adhesive using surface treatment of SiO2 nano fillers by glycidoxypropyltrimethoxysilane (GPTMS). For this purpose, the nano silica particles were silanized via a facile sol–gel method at silane concentrations of 1, 5, 10 and 20X (i.e. X is stoichiometric silane concentration). The nanoparticles were characterized carefully by FTIR, TGA, XRD and XPS techniques. It was found that the highest GPTMS grafting ratio was obtained at silane concentration of 10X. The pure and silanized nanoparticles were added to a two-pack epoxy resin and were compared for tensile and compressive properties. It was found that surface modification of nano silica caused improvement in the strength, modulus, compressive strength and compressive modulus by 56, 81, 200 and 66% compared to the pristine epoxy adhesive and also 70, 20, 17 and 21% compared to the pure nano silica containing adhesive. It also caused 40 and 25% improvement in the pullout strength, 33 and 18% enhancement in the pullout displacement and 130 and 50% in adhesion energy compared to the pristine and raw silica-containing adhesives, respectively.

Research advances in preparation, mechanism and application of thermally conductive and electrically insulating polymer composites in thermal management materials: A review

Today, electronic components are gradually developing towards miniaturization and multi-function. During the use of electronic components, a large amount of heat will be generated, which seriously limits the performance and service life of electronic components. Therefore, the preparation of thermal management material (TMMs) with high thermal conductivity (λ) can effectively solve the problem of thermal accumulation in electronic components. Compared with the preparation of intrinsic thermal conductive polymer composite, the method of filling thermal conductive filler in polymer matrix can better improve the λ of polymer composite. This review discusses the heat conduction mechanism of polymer and the factors affecting λ of polymer composites, including the type of filler, the shape and distribution of filler, and the functional surface treatment of filler. Then, the different methods of preparing thermally conductive and electrically insulating polymer composites (TCEIPCs) are introduced in detail. The application of polymer composites in thermal management is also introduced.

Enhanced thermal conductivity and rheological performance of epoxy and liquid crystal epoxy composites with filled Al2O3 compound

The heat dissipation capability of electrical insulation materials has been the bottleneck affecting the development of high power density electrical equipment and electronic devices. In this study, we investigated the effect of filler compounding, filler surface treatment and liquid crystal structure on the microscopic morphology, rheological performance, thermal conductivity and dielectric performance of the epoxy resin (EP) and liquid crystal epoxy resin (LCEP) composites. The results show that the composite with 45 μm and 3 μm Al2O3 compound fillers at a ratio of 3:2 showed a reduction in viscosity for about 1/3-1/30 and an enhancement in thermal conductivity for about 10%–40% compared to the other filler compounds with different filler size and ratio. The filler surface treatment by silane coupling agent diminished the viscosity by up to 90% and simultaneously enhanced the thermal conductivity of the composite by about 10%. The composite with LCEP matrix showed a thermal conductivity up to 2.47 W/(m·K) at 80 wt% filler loading, which is about 0.54 W/(m·K) higher than that of EP based composite. Moreover, the filler surface treatment can improve the electrical breakdown strength and volume resistivity of the composites. The results indicate that filler compound optimization, filler surface treatment and LCEP matrix can significantly improve the thermal conductivity, rheological and dielectric properties of the composites.

Effect of Alumina Modified by Silane on the Mechanical, Swelling and Dielectric Properties of Al2O3/EPDM/SBR Blend Composites

Rubber blending has been widely used to improve various properties in finished rubber products. The purpose of this paper is to investigate the effect of filler size, type, concentration, and surface treatment on the mechanical, swelling, dielectric, and morphology properties of ethylene propylene diene rubber (EPDM)/styrene-butadiene rubber (SBR) rubber blend nanocomposites filled with alumina (Al2O3) nanoparticles. Bis-(3-(triethoxysilyl)-propyl)-tetrasulfide (TESPT) was used as a silane coupling agent. Rubber blend nanocomposites containing Al2O3 nanoparticles were compared to carbon black (CB). The results indicate that the nanocomposites prepared, in particular with the TESPT, had better properties than the composites without the TESPT. Mechanical properties of the CB-filled EPDM/SBR rubber blend were noticeably improved, indicating CB's inherent reinforcing potential. We found that rubber nanocomposites' crosslink density and filler–rubber interaction increase, and the swelling coefficient decreases with increasing filler content. The dielectric properties of the nanocomposites showed a significant enhancement with fillers. SEM images showed that the CB sample had a higher distribution than Al2O3 due to good interaction and dispersion. This study's experimental data will help design and manufacture outdoor insulators.

Morphological, crystallinity and thermal stability characterization of poly(3-hydroxybutyrate-Co-3-hydroxyhexanoate)/zinc oxide nanoparticles bionanocomposites: Effect of filler content

Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx)/ZnO-NP nanoparticles bionanocomposites were elaborated by melt compounding in a twin-screw extruder at content ratio of 1.5, 3 and 6 wt.%. Morphology, crystallinity and thermal stability of the PHBHHx-based bionanocomposite samples were investigated by scanning electron microscopy (SEM), wide angle X-ray Diffraction (WAXD) and thermogravimetric analysis (TGA) aiming at evaluating the structure-properties relationships with respect to filler content and to neat PHBHHx. Morphological observations by SEM of the fractured surface of the bionanocomposite samples showed that ZnO-NP was randomly dispersed in PHBHHx matrix, with however a noticeable presence of filler aggregates at 6 wt.%. WAXD patterns displayed an increase in crystallinity of PHBHHx bionanocomposites with increasing ZnO-NP content, whereas TGA data indicated a decrease in thermal stability in comparison with the neat polymer. This result showed that the addition of ZnO-NP promoted the thermal degradation of PHBHHx through a random chain scission mechanism. Moreover, it was found that beyond 3 wt.% of filler content, no significant change was observed in the properties of PHBHHx/ZnO-NP bionanocomposites. The study highlighted the potential use of ZnO-NP at low content, as reinforcement in PHBHHx without necessarily carrying out any filler surface treatment nor solvent casting process.

Non-thermal plasma for surface treatment of inorganic fillers added to resin-based cements.

This study aims to evaluate the effect of non-thermal plasma (NTP) surface treatment in two composite inorganic fillers and evaluate their impact on the chemical-mechanical properties and bond strength ability of experimental resin cements. Ytterbium fluoride (YF) and barium silicate glass (BS) were characterized and submitted to different surface treatments: non-thermal plasma (NTP); non-thermal plasma and 3-(trimethoxysilyl) propyl methacrylate silanization; and 3-(trimethoxysilyl) propyl methacrylate silanization. Untreated fillers were used as a control. The fillers were incorporated at 65wt% concentration into light-cured experimental resin cements (50wt% BisGMA; 25wt% UDMA; 25wt% TEGDMA; 1mol% CQ). The degree of conversion, the flexural strength, and the microshear bond strength (μSBS) were evaluated to characterize developed composites. YF and BS were successfully cleaned with NTP treatment. Nor NTP neither the silanization affected the degree of conversion of resin cements. The NTP predicted an increase in YF-containing resin cements flexural strength, reducing the storage impact in these materials. NTP treatment did not affect the μSBS when applied to YF, while silanization was effective for BS-containing materials. NTP treatment of inorganic particles was possible and was shown to reduce the amount of organic contamination of the particle surface. YF surface treatment with NTP can be an alternative to improve the organic/inorganic interaction in resin composites to obtain materials with better mechanical properties. Surface cleaning with NTP may be an alternative for particle surface cleaning to enhance organic-inorganic interaction in dental composites resulting in improved mechanical strength of experimental resin cements.

Rubberized geopolymer composites: Effect of filler surface treatment

Existing waste tire management strategies such as landfill, warehousing, incineration, and pyrolysis are associated with significant emissions of hazardous compounds including gases, heavy metals, and oils. A sustainable rubber waste disposal strategy is immobilizing them in a crushed form in eco-friendly geopolymer (GP) matrices. However, the implementation of this approach is constrained by the strength degradation of rubberized geopolymer composites. In order to solve this problem, this article includes a comparative investigation of the effect of various physical and chemical pre-treatments of tire crumb rubber (CR) with NaOH, H2SO4, (CH3)2CO and KMnO₄ solutions, as well as ultraviolet radiation, on the mechanical performances and microstructure of rubberized fly ash-based GP composites. It has been established that the best effects are demonstrated by treatment with an aqueous solution of potassium permanganate; oxidative reactions with the solution lead to the formation of surface-active functional groups on the rubber. As a result, there is more than a twofold increase in the hydrophilicity of CR particles, estimated from the mass of adsorbed water vapor (from 1.5 to 3.3 wt%). This provides a strong adhesive contact of the filler with the geopolymer matrix, which favorably affects the change in the mechanical properties of the composites. The compressive strength in this case has been increased from 12.8 MPa (GP/untreated CR composite) to 15.5 MPa at addition of 10.0 wt% KMnO4 treated CR. Further optimization of the composition and of the curing mode of the geopolymer binder can potentially provide an additional positive effect in this aspect.

Photopolymerization shrinkage-stress reduction in polymer-based dental restoratives by surface modification of fillers

ObjectivesThis research explores the use of polymer brushes for surface treatment of fillers used in polymer-based dental restoratives with focus on shrinkage stress reduction. The influence of interfacial reactive groups on shrinkage stress is explored. MethodsOligomers of varying lengths and with varying number of reactive groups along the length were synthesized by modifying commercial oligomers. Surface of silica fillers (OX50) was treated with methylaminopropyltrimethoxysilane and this was further reacted with the synthesized oligomers to obtain a series of polymer brushes on the surface. Fillers modified with γ-methacryloxypropyltrimethoxysilane were used as a control. Filler surface treatment was confirmed using diffuse reflectance spectroscopy and thermogravimetric analysis. Fillers were added at 30 wt % to a resin made of BisGMA/TEGDMA and polymerization kinetics, shrinkage stress, volumetric shrinkage, flexural strength and modulus, viscosity were measured. ResultsComposites with polymer brush functionalized fillers showed up to a 30 % reduction in shrinkage stress as compared to the control, with no reduction in flexural strength and modulus. Shrinkage stress reduced with increasing length of the polymer brush and increased with increase in number of reactive groups along the length of the polymer brush. SignificanceThe interface between inorganic fillers and an organic polymer matrix has been utilized to reduce shrinkage stress in a composite with no compromise in mechanical properties. This study gives insights into the stress development mechanism at the interface.

Enhancement of Acid Stability of Silicone Elastomers by Using Inert Fillers

This paper shows a novel approach to reduce the aging of silicone elastomers for outdoor insulators by using different filler surface treatments and inert fillers such as barium sulphate (BaSO4). Silicone rubber composite insulators are used in overhead transmission lines (OHTL) since many years, however under specific environmental conditions, they can show a reduction of mechanical properties, embrittlement and the formation of superficial cracks. Besides other factors, these aging effects can be attributed to strong acids, which can be generated by high electrical field stresses and acidic pollution on the insulator surface. In this study, silicone elastomers used for outdoor insulation, were equipped with aluminum hydroxide with various surface treatments and inert fillers, which provokes a significant improvement of aging performance. Silicone elastomer compounds equipped with barium sulphate show improved aging resistance under acidic environment, like a reduced mass loss when immersed in concentrated nitric acid, decreased crack formation and enhanced stability of mechanical properties with comparable erosion resistance.

Recent Advances in Preparation, Mechanisms, and Applications of Thermally Conductive Polymer Composites: A Review

At present, the rapid accumulation of heat and the heat dissipation of electronic equipment and related components are important reasons that restrict the miniaturization, high integration, and high power of electronic equipment. It seriously affects the performance and life of electronic devices. Hence, improving the thermal conductivity of polymer composites (TCPCs) is the key to solving this problem. Compared with manufacturing intrinsic thermally conductive polymer composites, the method of filling the polymer matrix with thermally conductive fillers can better-enhance the thermal conductivity (λ) of the composites. This review starts from the thermal conduction mechanism and describes the factors affecting the λ of polymer composites, including filler type, filler morphology and distribution, and the functional surface treatment of fillers. Next, we introduce the preparation methods of filled thermally conductive polymer composites with different filler types. In addition, some commonly used thermal-conductivity theoretical models have been introduced to better-analyze the thermophysical properties of polymer composites. We discuss the simulation of λ and the thermal conduction process of polymer composites based on molecular dynamics and finite element analysis methods. Meanwhile, we briefly introduce the application of polymer composites in thermal management. Finally, we outline the challenges and prospects of TCPCs.

Upcycling of Vine Shoots: Production of Fillers for PHBV-Based Biocomposite Applications

This paper aims at investigating the potential of vine shoots (ViSh) upcycling as fillers in novel poly(3-hydroxybutyrate-3-hydroxyvalerate) (PHBV) based biocomposites. ViSh particles of around 50 µm (apparent median diameter) were obtained combining dry grinding processes, and mixed with PHBV using melt extrusion. Thermal stability and elongation at break of biocomposites were reduced with increasing contents of ViSh particles (10, 20 and 30 wt%), while Young’s modulus and water vapor permeability were increased. It was shown that a surface gas-phase esterification allowed to significantly increase the hydrophobicity of ViSh particles (increase of water contact angles from 59° to 114°), leading to a reduction of 27% in the water vapor permeability of the biocomposite filled with 30 wt% of ViSh. The overall mechanical performance was not impacted by gas-phase esterification, demonstrating that the interfacial adhesion between the virgin ViSh particles and the PHBV matrix was already good and that such filler surface treatment was not required in that case. It was concluded that ViSh particles can be interestingly used as low cost fillers in PHBV-based biocomposites to decrease the overall cost of materials.

Synergetic enhancement of thermal conductivity by constructing BN and AlN hybrid network in epoxy matrix

Thermal management has developed into a severe issue with the evolution of electronics. The construction of effectively thermal conduction pathways in the matrix is crucial for highly thermal conductive composites. In this work, a unique thermal conductive channel in the epoxy matrix had been established with hybridizing hexagonal boron nitride (BN) sheets and aluminum nitride (AlN) particles through a solution mixture and hot-pressing method. Synergetic enhancement of thermal conductivity was observed between BN and AlN fillers owing to the better dispersion of hybrid fillers, which created more pathways for phonon transport. With 40 vol% hybrid BN-AlN filler contents, the thermal conductivity of EP composite reached 2.4 Wm−1 K−1, eightfold increasing over the pristine epoxy matrix and two times to that of single BN or AlN filling composite. Moreover, the thermal conductivity of hybrid composite was further improved by more than 10% through the surface treatment of fillers with silane couple agents owing to the enhancement of interaction in composites. This study is of critical importance for composites used in electronics and electric equipment.

Influence of the organic matrix composition on the polymerization behavior and bulk properties of resin composites containing thiourethane-functionalized fillers

ObjectivesThe incorporation of thiourethane-based oligomeric additives into resin composite formulations leads to improvement in mechanical properties and reduction in polymerization stress, but may increase viscosity. The objective of this study was to functionalize filler particle surfaces with thiourethane silane molecules and determine the impact of the inorganic filler loading and surface treatment on the behavior of experimental resin composites with systematically-varied organic matrices. MethodsThiourethane oligomer was synthesized de novo, and grafted to the surface of 0.7um barium glass. BisGMA and TEGDMA (BT) were combined (at 30:70, 50:50 or 70:30 wt%) to 50 or 75 wt% of methacrylate (MA-Sil – control) or thiourethane-silanized (TU-Sil) particles. Composites were made polymerizable by the addition of 0.2 wt% BAPO and 0.05 wt% BHT was added as inhibitor. A mercury arc lamp (320–500 nm) at 800 mW/cm2 was used for all curing procedures. Kinetics of polymerization was assessed by near-IR spectroscopy in real time. Polymerization stress was determined with a cantilever system in real time (Bioman). Flexural modulus and strength were determined in 3-point bending (25 × 2 × 2 mm). Water sorption and solubility and film thickness were tested according to ISO 4049. Polymeric network characteristics were analyzed by dynamic mechanical analysis (DMA). Data was analyzed with two-way ANOVA/Tukey’s test (95%). ResultsViscosity increased with the increase in BisGMA and/or filler amounts. Overall, TU-Sil containing composites showed delayed vitrification and higher final DC. Filler concentration did not affect DC neither flexural strength. DC decreased with increasing BisGMA content. Polymerization stress reduced and flexural modulus increased for higher filler content, especially for formulations containing TU-Sil particles. The water stability was positively affected by the increase in amount of BisGMA and inorganic filler particles. In terms of polymeric network, the addition of TU-Sil particles increased the Tg and decreased the E′ and cross-link density. ConclusionsWith the exception of flexural modulus, all tested properties were significantly impacted by the matrix viscosity and/or the addition of TU-Sil filler particles. In general, the use of thiourethane oligomers as a silane coupling agent was able to reinforce the materials and reduce the polymerization stress without negatively affecting the viscosity of the system.

Fabrication of Porous Recycled HDPE Biocomposites Foam: Effect of Rice Husk Filler Contents and Surface Treatments on the Mechanical Properties.

In this study, a biodegradable, cheap and durable recycled high-density polyethylene (rHDPE) polymer reinforced with rice husk (RH) fibre was fabricated into a foam structure through several processes, including extrusion, internal mixing and hot pressing. The effect of filler loading on the properties of the foam and the influence of RH surface treatments on the filler–matrix adhesion and mechanical properties of the composite foam were investigated. The morphological examination shows that 50 wt.% filler content resulted in an effective dispersion of cells with the smallest cell size (58.3 µm) and the highest density (7.62 × 1011 sel/cm3). This small cell size benefits the mechanical properties. Results indicate that the tensile strength and the Young’s modulus of the alkali-treated RH/rHDPE composite foam are the highest amongst the treatments (10.83 MPa and 858 MPa, respectively), followed by UV/O3, which has shown considerable increments compared with the untreated composite. The flexural and impact tests also show the increment in strength for the composite foam after chemical treatment. Although the UV/O3 surface treatment has minor influence on the mechanical enhancement of the composite foam, this method may be a reliable surface treatment of the fibre-reinforced composite.

Effects of nanoparticles size and interactions on dielectric properties of polymer matrix flexible dielectric nanocomposites

Effects of particle size on the dielectric properties of polymer matrix flexible nanocomposites were studied. Synthesized barium titanate (BaTiO3; BT) nanoparticles (NPs) with different sizes were effectively dispersed in the matrix polymer using a simple phase separation method. The dielectric responses of free-standing thin composite films were studied by impedance spectroscopy. The interactions between nanoparticles were also studied by finite element analysis and compared with experimental data using a time harmonic-electric current solver in the AC/DC module of COMSOL Multiphysics® 5.2. The dielectric permittivity of polymer matrix nanocomposites was remarkably affected by the BT particle size, while the dielectric loss did not show any noticeable changes. The real permittivity exhibited the highest value when the BT particle size was near 100 nm. The calculated energy density based on measured real permittivity and breakdown strength was as high as 17.24 J/cm3. The dielectric properties of polymer matrix nanocomposites can be improved by controlling the particle size of nanofillers in conjunction with surface treatment of fillers.

Nanogel-Based Filler-Matrix Interphase for Polymerization Stress Reduction

A novel filler-resin matrix interphase structure was developed and evaluated for dental composite restoratives. Nanogel additives were chemically attached to the filler surface to use this created interphase as a potential source of compliance to minimize stress development during polymerization. In addition, we evaluated the effects of free nanogel dispersion into the resin matrix, combined or not with nanogel-modified fillers. Nanogels with varied characteristics were synthesized (i.e., size, 5 and 11 nm; glass transition temperature, 28 °C to 65 °C). Glass fillers were treated with trimethoxyvinylsilane and further reacted with thiol-functionalized nanogels via a free radical thiol-ene reaction. γ-Methacryloxypropyltrimethoxysilane-surface treated fillers were used as a control. Composites were formulated with BisGMA/TEGDMA resin blend with 60 wt% fillers with nanogel-modified fillers and/or free nanogel additives at 15 wt% in the resin phase. Polymerization kinetics, polymerization stress, volumetric shrinkage, and rheological and mechanical properties were evaluated to provide comprehensive characterization. Nanogel-modified fillers significantly reduced the polymerization stress from 2.2 MPa to 1.7 to 1.4 MPa, resulting in 20% stress reduction. A significantly greater nanogel content was required to generate the same magnitude stress reduction when the nanogels were dispersed only in the resin phase. When the nanogel-modified filler surface treatment and resin-dispersed nanogel strategies were combined, there was a stress reduction of 50% (values of 1.2 to 1.1 MPa). Polymerization rate and volumetric shrinkage were significantly reduced for systems with nanogel additives into the resin. Notably, the flexural modulus of the materials was not compromised, although a slight reduction in flexural strength associated with the nanogel-modified interphase was observed. Overall, modest amounts of free nanogel additives in the resin phase can be effectively combined with a limited nanogel content filler-resin interphase to lower volumetric shrinkage and dramatically reduce overall polymerization stress of composites.