Maximum Storage Modulus Research Articles

Borax Cross-Linked Acrylamide-Grafted Starch Self-Healing Hydrogels.

The biocompatibility and renewability of starch-based hydrogels have made them popular for applications across various sectors. Their tendency to incur damage after repeated use limits their effectiveness in practical applications. Improving the mechanical properties and self-healing of hydrogels simultaneously remains a challenge. This study introduces a new self-healing hydrogel, synthesized by grafting acrylamide onto starch using ceric ammonium nitrate (CAN) as an initiator, followed by borax cross-linking. We systematically examined how the starch-to-monomer ratio, borax concentration, and CAN concentration impact the grafting reactions and overall performance of the hydrogels. The addition of borax significantly reinforced the strength of the hydrogel; the maximum storage modulus increased by 1.8 times. Thanks to dynamic borate ester and hydrogen bonding, the hydrogel demonstrated remarkable recovery properties and responsiveness to temperature. We expect that the present research could broaden the application of starch-based hydrogels in agriculture, sensors, and wastewater treatment.

Covalent Pectin/Arabinoxylan Hydrogels: Rheological and Microstructural Characterization.

This research aimed to evaluate the gelation process of ferulated pectin (FP) and ferulated arabinoxylan (AXF) in a new mixed hydrogel and determine its microstructural characteristics. FP from sugar beet (Beta vulgaris) and arabinoxylan from maize (Zea mays) bran were gelled via oxidative coupling using laccase as a crosslinking agent. The dynamic oscillatory rheology of the mixed hydrogel revealed a maximum storage modulus of 768 Pa after 60 min. The scanning electron microscopy images showed that mixed hydrogels possess a microstructure of imperfect honeycomb. The ferulic acid content of the mixed hydrogel was 3.73 mg/g, and ferulic acid dimer 8-5' was the most abundant. The presence of a trimer was also detected. This study reports the distribution and concentration of ferulic acid dimers, and the rheological and microstructural properties of a mixed hydrogel based on FP and AXF, which has promising features as a new covalent biopolymeric material.

Development of beetroot powder-enriched inks for 3D food printing based on hydrogel/oleogel bigels

3D printing with bigel inks exhibits substantial potential for food structuring and nutritional innovation, particularly through the enrichment of foods with vegetables rich in health-promoting bioactive compounds. This study focuses on the preparation of bigels incorporating beetroot powder. Hydrogels based on xanthan gum, carrageenan, and guar gum were used in combination with monoglyceride oleogels to formulate suitable inks for extrusion-based 3D food printing. This study investigated the effects of hydrogel type, vegetable powder content, and hydrogel:oleogel mass ratio on the microstructure, rheological properties, and extrusion behavior of the bigels. Furthermore, the printability of the selected formulations was evaluated. The inclusion of beetroot powder enhanced the structure and mechanical strength of all the hydrogels. Bigels prepared with an 80:20 mass ratio yielded homogeneous materials for all three hydrogelators. They exhibited maximum storage modulus values of 1.1E4, 7.8E3, and 3.3E3 Pa for guar gum, carrageenan, and xanthan gum, respectively. Moreover, these bigels partially recovered of their initial structure after the application of high strain and demonstrated appropriate flowability for extrusion through 1.2 and 2 mm 3D printer nozzles. Successful printing of 2D (grid) and 3D (cube) structures was achieved using guar gum-based bigels, followed by carrageenan-based counterparts, which displayed superior dimensional accuracy, structural integrity, enhanced line resolution, and minimal printing errors and deformations. These findings provide valuable insights and lay the groundwork for developing more complex and functional food structures.

Effects of the Amylose/Amylopectin Ratio of Starch on Borax-Crosslinked Hydrogels.

Herein, we simultaneously prepared borax-crosslinked starch-based hydrogels with enhanced mechanical properties and self-healing ability via a simple one-pot method. The focus of this work is to study the effects of the amylose/amylopectin ratio of starch on the grafting reactions and the performance of the resulting borax-crosslinked hydrogels. An increase in the amylose/ amylopectin ratio increased the gel fraction and grafting ratio but decreased the swelling ratio and pore diameter. Compared with hydrogels prepared from low-amylose starches, hydrogels prepared from high-amylose starches showed pronouncedly increased network strength, and the maximum storage modulus increased by 8.54 times because unbranched amylose offered more hydroxyl groups to form dynamic borate ester bonds with borate ions and intermolecular hydrogen bonds, leading to an enhanced crosslink density. In addition, all the hydrogels exhibited a uniformly interconnected network structure. Furthermore, owing to the dynamic borate ester bonds and hydrogen bonds, the hydrogel exhibited excellent recovery behavior under continuous step strain, and it also showed thermal responsiveness.

Experimental investigation on the thermal characteristics of Kevlar/hemp intraply hybrid composites: Influence of various weaving designs

In this work, several weaving designs of intra-ply woven fabric Kevlar/hemp fiber (KHE) reinforced epoxy hybrid composites are developed and their thermal characteristics are examined. Thermogravimetric analysis showed that intra-ply hybrid of plain and basket weave designs possessed highest thermal stability. The different weaving patterns of KHE hybrid composites have no effect on the glass transmission temperature (Tg) value as inferred from the differential scanning calorimetry results. The thermomechanical analysis clearly demonstrates the superior dimension stability of the hybrid composites with basket weave. Dynamic mechanical analysis reveals that twill weave KHE have exhibited the maximum storage modulus (2021 MPa), loss modulus (210 MPa) and lower tan delta (0.3090) values compared to all other composites. Based on the obtained results, it is denoted that all the fabricated KHE hybrid composites displayed improved thermal performance. It may be suitable for applications in thermal insulation panels, fire-resistant clothing, and automotive underbody shields.

The rigid-flexible balanced molecular crosslinking network transition interface: An effective strategy for improving the performance of bamboo fibers/poly(butadiene succinate-co-butadiene adipate) biocomposites

The poor interfacial compatibility of natural fiber-reinforced polymer composites has become a major challenge in the development of industry-standard high-performance composites. To solve this problem, this study constructs a novel rigid-flexible balanced molecular crosslinked network transition interface in composites. The interface improves the interfacial compatibility of the composites by balancing the stiffness and strength of the fibers and the matrix， effectively improving the properties of the composites. The flexural strength and flexural modulus of the composites were enhanced by 38 % and 44 %, respectively. Water absorption decreased by 30 %. The initial and maximum thermal degradation temperatures increased by 20 °C and 16 °C, respectively. The maximum storage modulus increased by 316 %. Furthermore, the impact toughness was elevated by 41 %, attributed to the crosslinked network's efficacy in absorbing and dissipating externally applied energy. This innovative approach introduces a new theory of interfacial reinforcement compatibility, advancing the development of high-performance and sustainable biocomposites.

Effect of sepiolite on the rheological properties of shear thickening fluid and improvement mechanism analysis

To improve the performance of shear thickening fluids (STFs), we propose the addition of fibrous sepiolite. Through macroscopic rheological tests and microscopic characterization, the effects of different sepiolite mass fractions (0 wt%, 1 wt%, 2 wt% and 3 wt%) on the shear thickening of a SiO2-STF system (with a PEG200 dispersion medium) at different ambient temperatures (20 °C, 30 °C, 40 °C and 50 °C) were investigated. Rheological experiments revealed a significant improvement in the shear thickening of SiO2-STF with the addition of sepiolite (Sep/SiO2-STF), with 7.11- and 1.94-fold increases in absolute and relative shear thickening, respectively. As the sepiolite mass fraction increased from 0 wt% to 3 wt%, the temperature sensitivity coefficient decreased from 13.493 to 4.839, indicating that the Sep/SiO2-STF system still exhibited favourable shear thickening at 50 °C. Dynamic oscillatory shear testing revealed that with an increase in sepiolite mass fraction from 0 wt% to 3 wt%, the maximum energy storage modulus, maximum energy dissipation modulus and shear stress increased by 5196.25 %, 1676.16 % and 377.54 %, respectively. Microscopic characterization revealed that sepiolite induced the formation of more clusters in the STF system primarily through the physical adsorption of silica particles and Si–OH on its surface, leading to a significant increase in the shear thickening effect.

Photocurable comb polyamic acid for solvent-free direct ink writing with low dimensional shrinkage

Polyimides are high-performance organic polymers with excellent insulation, high-temperature resistance, and mechanical properties. However, their poor solubility makes it challenging to use them to prepare solvent-free high-performance photocurable polyimide inks with low dimensional shrinkage. In this study, photocurable comb polyamic acid resins were synthesized, and their solubility was examined based on density functional theory (DFT) calculations. Experiments showed that polyamic acid resins with specific topologies could be dissolved in photocurable monomers to prepare solvent-free photocured polyimide inks. A custom-made UV-assisted direct ink writing 3D printer was used to fabricate complex three-dimensional devices. Further heat treatment caused the polyamic acids to undergo dehydration and cyclization into rigid polyimide structures, and this process exhibited less than 6% dimensional shrinkage. The final material had a maximum storage modulus of 3.1 GPa (40 ℃) and a glass transition temperature of 204 ℃. The good comprehensive performance suggests great potential for aerospace applications.

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.

Surface Roughness, Dynamic Wettability, and Interphase of Modified Melamine Formaldehyde-Based Adhesives on Jabon Wood.

The surface roughness and wettability of wood are critical aspects to consider when producing laminated wood products with adhesive applications. This study aims to investigate the surface roughness and dynamic wettability of Jabon wood in the presence of melamine formaldehyde (MF)-based adhesives. Commercial MF adhesives (MF-0) and modified MF adhesives (MF-1) were applied to Jabon wood, which includes tangential (T), radial (R), and semi-radial (T/R) surfaces. The surface roughness of Jabon wood was assessed using a portable stylus-type profilometer. The low-bond axisymmetric drop shape analysis (LB-ADSA) method was employed to identify the contact angle (θ) of the MF-based adhesives on Jabon wood. The wettability was determined by evaluating the constant contact angle change rate (K value) using the Shi and Gardner (S/G) model. Dynamic mechanical analysis (DMA) was employed to investigate the viscoelastic characteristics of the interphase analysis of the wood and MF-based adhesives. The roughness level (Ra) of the Jabon board ranged from 5.62 to 6.94 µm, with the T/R having a higher level of roughness than the R and T. MF-0 exhibited a higher K value (0.262-0.331) than MF-1 (0.136-0.212), indicating that MF-0 wets the surface of Jabon wood more easily than MF-1. The wood-MF-0 interphase reached a maximum stiffness of 957 N/m at 123.0 °C, while the wood-MF-1 had a maximum stiffness of 2734 N/m at 110.5 °C. In addition, the wood-MF-0 had a maximum storage modulus of 12,650 MPa at a temperature of 128.9 °C, while the wood-MF-1 had a maximum storage modulus of 22,950 MPa at 113.5 °C.

Shear-stiffening porous material with impact-hardening functionality: Application in hydrogen explosion safety protection

In this study, a shear-stiffening composite porous material (PU@CS) was developed using the dipping-drying technique, with polyurethane (PU) as the substrate. PU@CS not only overcomes the cold flow drawbacks of shear-stiffening gel (SSG) but also significantly enhances the mechanical properties of PU (with a one-order-of-magnitude increase in maximum storage modulus). The introduction of multi-walled carbon nanotubes (MWCNTs) overcomes the electrostatic aggregation drawback of PU. Due to its outstanding shear hardening effect, PU@CS exhibits superior explosion-proof compared to PU, and when filled to a length of 50 cm, it achieves complete quenching of hydrogen gas explosion flames, with a maximum explosion overpressure attenuation ratio of 87.2%. This work provides data support for the application of SSG in the field of explosion protection.

Effects of hydrocolloids on mechanical properties, viscoelastic and microstructural properties of starch-based modeling clay

The effects of various hydrocolloids (guar gum, xanthan gum, and carboxymethyl cellulose) on the texture, rheology, and microstructural properties of modeling clay prepared with cassava starch were investigated. Notably, incorporation of 3 % guar gum and 4 % xanthan gum into starch-based modeling clay resulted in enhancements of 94.12 % and 77.47 % in cohesiveness, and 64.70 % and 66.20 % in extensibility, respectively. For starch-based modeling clay with added guar gum and xanthan gum, compared to formulations without hydrocolloids, the linear viscoelastic range exceeded 0.04 %, and the frequency dependence of both maximum creep compliance (Jmax) and storage modulus (G′) was significantly reduced. This indicates a more stable network structure and enhanced resistance to deformation. Results from Fourier Transform Infrared (FTIR) spectroscopy and X-ray diffraction (XRD) confirmed that the physical interactions between starch and various hydrocolloids, along with the addition of these hydrocolloids, inhibited the degradation effect of thermomechanical processing on the crystalline structure of starch. With the addition of guar gum, it is observed that a continuous and dense network structure forms within the starch-based modeling clay, and starch particles are distributed uniformly. In conclusion, hydrocolloids enhances the properties of starch-based modeling clay, introducing an innovative solution to the modeling clay sector.

Performance of Particleboard Made of Agroforestry Residues Bonded with Thermosetting Adhesive Derived from Waste Styrofoam.

This paper investigated the upcycling process of thermoplastic waste polystyrene (WPS) into thermosetting particleboard adhesive using two cross-linkers, namely methylene diphenyl diisocyanate (MDI) and maleic anhydride (MA). The WPS was dissolved in an organic co-solvent. The weight ratio of WPS/co-solvent was 1:9, and 10% of cross-linkers based on the WPS solids content were added subsequently at 60 °C under continuous stirring for 30 min. The adhesive properties, cohesion strength, and thermo-mechanical properties of WPS-based adhesives were examined to investigate the change of thermoplastic WPS to thermosetting adhesives. The bonding strength of WPS-based adhesives was evaluated in particleboard made of sengon (Falcataria moluccana (Miq.) Barneby & J.W. Grimes) wood and rice straw particles at different weight ratios according to the Japanese Industrial Standard (JIS) A 5908:2003. Rheology and Dynamic Mechanical Analysis revealed that modification with MDI and MA resulted in thermosetting properties in WPS-based adhesives by increasing the viscosity at a temperature above 72.7 °C and reaching the maximum storage modulus above 90.8 °C. WPS modified with MDI had a lower activation energy (Ea) value (83.4 kJ/mole) compared to the WPS modified with MA (150.8 kJ/mole), indicating the cross-linking with MDI was much faster compared with MA. Particleboard fabricated from 100% sengon wood particles bonded with WPS modified with MDI fulfilled the minimum requirement of JIS A 5908:2003 for interior applications.

Gel properties and interactions of hydrogels constructed with low acyl gellan gum and puerarin

To develop composite hydrogels based on low acyl gellan gum (GG), the effect of puerarin (PUE) on the gel properties of GG was investigated. The results showed that the maximum storage modulus (G′) of the 1.2 % GG/0.8 % PUE composite hydrogel was 377.4 Pa at 0.1 Hz, which was enhanced by 4.7-fold compared with that of 1.2 % GG. The melting temperature of this composite hydrogel increased from 74.1 °C to >80.0 °C. LF-NMR results showed that a significant amount of free water was present in the hydrogel matrix. The surface structure aggregation and the shrinkage of the honeycomb meshes in the composite hydrogel proved the cross-linking of PUE and GG. XRD, FTIR and molecular simulation results illustrated that hydrogen bonds were the most important factor controlling the interaction between GG and PUE. Thus, the GG/PUE composite hydrogel has good elasticity, thermal stability and water retention, which lays a good foundation for further application in the food industry.

N-doped-GO@Zn nano-layers filled epoxy composite with superior mechanical and anti-corrosion properties

Fabrication of a durable corrosion-resistant epoxy coating with superior active and passive preservation features along with improved mechanical properties is the major target of this study. For this, the Nitrogen (N)-doped graphene oxide (NGO) nano-sheets were obtained in two conditions (I: plane and II: edge) and then modified with zinc ions as an inhibitor. The chemistry of the NGO-Zn nano-sheets was surveyed by FTIR and TGA methods. It was discovered from the EIS test outcomes that the entrance of 0.2 wt% of NGO-Zn nano-sheets into the epoxy coating supplied a strong protective system with considerably improved barrier properties and the emergence of active features. The hindrance properties of these nano-composite coatings were so excellent that the log |Z|10 mHz value experienced little changes even after 147 days of electrolyte attack. The active protection feature of the EP/NGOU-Zn and EP/NGU-Zn nano-containers in reference to Rt values after 48 h of immersion was concluded, displaying 1.3 and 1.7 times improvement. The Raman and FTIR test outcomes of the cured epoxy composites showed that the incorporation of fillers into the coating has no adverse effect on its curing behavior. Results disclosed that the NGO constructed with method II (NGU) greatly improved the mechanical properties of the polymeric matrix by about 50 %, recording maximum storage modulus (2021 MPa) in the dynamic mechanical thermal analysis (DMTA) test among all samples.

Effect of hybridization on camphor soot-embedded palmyra fiber-reinforced nylon nanocomposites

In the present study, camphor soot-filled palmyra fiber-reinforced nylon-6 hybrid nanocomposites (CPFNnC) were prepared using a twin-screw extruder with different wt% of CPFNnC (0, 3, 6 or 9 wt%). These composites were characterized to study their thermal, mechanical and rheological properties. Thermogravimetric analysis showed a marginal increase in thermal stability with 6 wt% CPFNnC. Differential scanning calorimetry curves showed a slight increment in the melting point in CPFNnC, while degradation temperature decreased with fiber content. Dynamic mechanical analysis indicated a maximum storage modulus for 6 wt% CPFNnC at 803 MPa compared with fiber-free nylon-6 (696 MPa at 25 °C). Tan δ for 3 wt% CPFNnC showed a better damping effect due to the existence of palmyra fibers. Creep results indicated that CPFNnC containing 6 wt% fibers has a minimum depth impression of 0.124 mm compared with fiber-free nylon with 0.146 mm. Scanning electron microscopy revealed a uniform distribution of modified palmyra fibers in the matrix and brittle fracture was observed in the CPFNnC. Compared with fiber-free nylon-6, the tensile strength, flexural strength and density of the CPFNnC increased with increase in fiber content; however, the impact strength was reduced and a lower melt flow index was found.

Effect of the alumina micro-particle sizes on the thermal conductivity and dynamic mechanical property of epoxy resin.

Epoxy thermal conductive adhesives with high thermal conductivity and dynamic mechanical properties are important thermally conductive materials for fabricating highly integrated electronic devices. In this paper, micro-Al2O3 is used as a thermally conductive filler for the epoxy resin composite and investigated the effect of micron-sized alumina particle size on the thermal conductivity and dynamic mechanical property of epoxy resin by the transient planar hot plate method and DMA (Dynamic mechanical analysis). The experimental results show that with the same amount of alumina filling, the thermal conductivity and Tg (glass transition temperature) of epoxy/Al2O3 composite material decrease with the increase of alumina particle size. The maximum thermal conductivity of the composite material is 0.679 (W/mK), while the energy storage modulus of epoxy/Al2O3 composite material increases with the increase of alumina particle size, and the maximum energy storage modulus of the composite material is 160MPa. Compared with pure epoxy resin, the thermal conductivity and energy storage modulus have increased by 2.7 and 3.2 times, respectively. The epoxy/Al2O3 composite was applied to the COB (Chips On Board) type LED package, and the substrate temperature of the LED dropped to the lowest after 1.5 hours of operation using EP-A5 composite, and the temperature was stabilized at 38.2°C, indicating that the addition of 5-micron alumina composite has the best heat dissipation in the COB type LED package. These results are critical for the implementation of particulate-filled polymer composites in practical applications because relaxed material specifications and handling procedures can be incorporated in production environments to improve efficiency.

Thermal stability and dynamic mechanical analysis of nano-biofillers blended hybrid composites reinforced by cellulosic Borassus flabellifer L. fiber

The aim of this study is to investigate the dynamic mechanical and thermal stability behavior of rice husk nano-biofillers blend epoxy hybrid composites reinforced by Borassus flabellifer L. leaf fiber. The raw Borassus leaf fibers were treated with 5 wt.% NaOH solution to reduce the disadvantages of hydroxyl bonding. Rice husk nano-fillers (RHNFs) were blended with epoxy resin to modify them with 0.25, 0.45, and 0.65 wt.%, respectively, using sonication and mechanical stirring process. The prepared samples were assessed to evaluate the thermal stability, maximum degradation temperature, storage modulus (E′), loss modulus (E″), damping factor (tan δ) and Cole–Cole plot of the composites. EDX spectroscopy was used to confirm the elemental composition of nano-biofillers. The morphology of RHNFs was analyzed using a scanning electron microscope (SEM). The TG analysis confirmed that the 0.45 wt.% RHNFs blended Borassus leaf fiber (BLF) composites exhibited superior thermal stability (371–384 °C). Derivative thermogravimetry (DTG) analysis exposed that the maximum mass-loss degradation temperature of 0.45 wt.% RHNFs blend composites was 411 °C for the first stage and 678 °C for the second stage, which were more than raw and RHNFs blend (0.25 and 0.65 wt.%) composites. Accordingly, improved E′ (959.16–1637.75 MPa), glass transition temperature (T g) from E″ (90.48–97.69 °C) and, T g from tan δ (103.35–109.67 °C) were derived from the modified composites. Owing to the improved dispersion of the nano-filler, the 0.45 wt.% RHNFs blend composites had a homogeneous polymer system, as verified by the Cole–Cole diagram. The analyzed composites are to be used with versatile functionality for their intended purpose.

Cellulose supported and strengthened shear stiffening gel with enhanced impact-resistant performance

Shear stiffening gel (SSG) is a promising cushioning material for impact-resistant applications as its moduli significantly increase under shear. However, SSG cannot retain its shape due to cold flow effect, which severely restricts its broad applications. In this study, both “top-down” and “bottom-up” strategies were respectively employed to construct cellulose supported and strengthened polyborosiloxane SSG (PSSG), resulting in stable shapes with significantly enhanced mechanical properties and impact-resistant performance attributed to reinforced concrete-like “steel-and-cement” structure. In “top-down” strategy, porous cellulose scaffolds (CS) were fabricated by removing lignin and hemicellulose from wood and then used as templates to encapsulate PSSG (PSSG@CS). In “bottom-up” strategy, cellulose nanofibers (CNFs) were well dispersed in PSSG and employed as nanofillers to strengthen PSSG (PSSG@CNF). Both PSSG@CS and PSSG@CNF effectively inhibited the cold flow deformation of PSSG and exhibited significantly enhanced shear stiffening properties. Rigid and hydrophobic PSSG@CS with fixed shape inherits the excellent mechanical properties of wood, with maximum storage modulus of 908 MPa, much higher than PSSG@CNF (15.3 MPa) and pristine PSSG (4.7 MPa). PSSG@CNF is flexible, self-healable, and adhesive, and could be processed to varied shapes. Both PSSG@CS and PSSG@CNF displayed outstanding impact-resistant performance when employed as protective cushion for glass.

Viscoelastic properties of alkaline treated walnut shell/rice straw fiber/epoxy biocomposite

The increasing demand for an eco-friendly environment has led to the recent development of polymer matrix/green plant fiber composites. In this present study, the viscoelastic performance of walnut/rice straw fiber/epoxy biocomposites was examined using a dynamic mechanical analysis (DMA) in three-point bending mode at a constant frequency (1 Hz) and temperature (25 oC to 240 °C). The surface morphology of the developed composites was analyzed using field emission scanning electron microscopy (SEM). The epoxy resin was incorporated with walnut/rice straw fiber in five proportions (2-10 wt%) using the hand lay-up technique. The hybrids of rice straw fiber/walnut shell ash particulates were added in equal ratios. The DMA results showed that epoxy/6wt% walnut/rice straw fiber biocomposite recorded the maximum storage modulus (> 8 × 103 MPa) with low loss modulus and damping factor. This indicates excellent stiffness and high energy storage capacity resulting from excellent interfacial bonding of molecules of epoxy, walnut shell particulates, and rice straw fiber. The epoxy/rice straw fiber biocomposite showed a high rate of molecular mobility, leading to high heat dissipation and damping capacity. The glass transition temperature (Tg) of the developed composites ranges from 70 oC to 130 oC, indicating the working temperature of the materials to be below 70 oC. The tan-δ curves indicate that walnut/rice straw fiber/epoxy biocomposites are heterogeneous materials with separate viscoelastic phases and glass transition temperatures, resulting from the addition of walnut shell particulates and rice straw fiber. These reinforcers are finally noted as critical factors affecting the extent of macromolecular mobility within walnut/rice straw fiber/epoxy biocomposites.