Tensile Measurements Research Articles

Impact resistance of self-sensing engineered cementitious composite (ECC) under different temperatures

Self-sensing engineered cementitious composite (ECC) is inevitably susceptible to the effects of impact loads when it is applied to structural health monitoring. In this paper, the impact resistance of self-sensing ECC under varying temperatures was investigated by experiments. Specimens comprising cement mortar, conventional ECC, and self-sensing ECC, all featuring identical water-binder ratios, were prepared and subjected to compressive and tensile strength evaluations, as well as tensile ductility measurements. Subsequently, the drop-weight impact tests were conducted on these three specimens at the temperatures of -50℃, -30℃, -10℃, 20℃, 50℃ and 100℃, respectively. Detailed analyses were carried out on the resulting impact loads, impact durations, dent depths, and failure modes. Our findings reveal that the compressive strength of cement mortar surpasses that of both conventional ECC and self-sensing ECC. Furthermore, conventional ECC and self-sensing ECC exhibit ultimate tensile strains of 4.6% and 6.7%, respectively. At the same drop-height of impactor, the maximum impact force decreases with the increase of temperature. At cold temperature, the specimen exhibit heightened impact forces coupled with abbreviated impact durations. Self-sensing ECC demonstrates a decreased maximum impact force and an extended duration compared to conventional ECC. The cement mortar specimen shows brittle failure, while both self-sensing ECC and conventional ECC align with the scabbing failure mode. Self-sensing ECC with a smaller scabbing thickness has preferable impact resistance and deformability.

A novel process for simultaneously improving the strength and plasticity of 18Ni(350) maraging steel

A novel process involving cold deformation, cyclic solution, and two-step aging is developed for simultaneously improving the strength and plasticity of 18Ni(350) maraging steel. The strengthening and toughening mechanisms are elucidated by microstructural characterization and tensile property measurements. Cold deformation and cyclic solution refine the final martensite grains. In addition, two-step aging ensures the formation of numerous fine precipitates and a small amount of fine reversed austenite. Ultra-high strength is achieved by a combination of solid-solution, grain refinement, dislocation, and precipitation strengthening, with the latter having the largest contribution. Compared with the traditional process, the UTS and elongation are increased by 9.13% and 22.83%, respectively, to 2511 MPa and 5.81%, demonstrating the effectiveness of this novel process.

Grain Structure and Tensile Properties of As-Cast and Aged Pb–1.1%Sn–0.05%Ca

Abstract The effects of temperature parameters of casting procedure and aging time at room temperature on the grain structure and tensile properties of Pb–1.1%Sn–0.05%Ca alloy for positive grids of lead-acid batteries were studied by means of optical metallography, scanning electron microscopy, and tensile properties measurements. It was established that with melt or mold temperatures rising, grains in the alloy structure become larger, which causes an increase in the elongation and a decrease in the ultimate tensile strength of the alloy. Natural aging for 32 days does not noticeably change grain size but affects tensile properties of the alloy. Final ultimate tensile strength, yield strength, and Young’s modulus are found to be 2.7, 4.9, and 1.3 times higher, respectively, but the elongation is 2.4 times lower because of the precipitation of intermetallic phases.

Characterization of 3D printed samples from biomass-fungi composite materials

Biomass-fungi composite materials are derived from sustainable sources and can biodegrade at the end of their service. In these composite materials, the biomass particles (made from agricultural waste such as hemp hurd) act as the substrate, and a network of fungal hyphae grow through and bind the biomass particles together. These composite materials can be used to manufacture products traditionally made from petroleum-based plastics. Potential applications of these products are in the packaging, furniture, and construction industries. Typically, molding-based methods are used to manufacture products using these composite materials. Recently, the authors reported a novel 3D printing-based method using these composite materials. This paper reports a follow-up investigation into the characterization of 3D printed samples from biomass-fungi composite materials. Tensile and compressive testing samples were shaped using molds from a portion of each printed sample. Mechanical properties of these tensile and compressive testing samples and chemical properties of the printed samples were measured. Tensile and compressive testing measurement results showed that, at the significance level of 0.05, effects of 3D printing parameters studied (printing speed and extrusion pressure) were not statistically significant on Young’s modulus and ultimate tensile strength of the tensile testing samples, as well as on compressive strength and compressive modulus of the compressive testing samples. Results obtained from the Fourier transform infrared spectroscopy analysis show that chemical composition of printed samples was consistent with the data in the literature.

Hypostomus plecostomus-inspired soft sucker to adsorb slippery tissues: a stabilizing post-valvular cavity and stiffness gradient materials provide excellent adsorption performance

The hard suckers commonly used in surgical operations often cause adsorption extrusion damage to the biological tissue. To tackle this problem, from the perspective of bionics, through in-depth observation and research on the special sucker adsorption process and adsorption mechanism of hypostomus plecostomus (HP), this paper proposes a bionic soft hypostomus plecostomus sucker (BSHPS) with a variable stiffness gradient structure with a good adsorption performance on soft moist irregular biological tissues. The BSHPS comprises a lip disc, a pre-valvular cavity, and a post-valvular cavity. Through the volume changes of the pre- and post-valvular cavities, a pressure difference is generated between the inside and outside of the sucker, enabling the lip disc to remain sealed. The experiments were carried out by an automatic tensile force measurement system equipped with a vacuum pump, and the results showed that in slippery environment, the adsorption performance of the BSHPS is improved by a maximum of 61.9% compared to that in dry environment. On a biological tissue surface, the adsorption force is as high as 13.7765 N. The most important advantage of the proposed BSHPS is that it can be firmly adsorbed the surface of soft moist irregular biological tissues, effectively slowing down or avoiding adsorption extrusion damage to the biological tissue. Therefore, the BSHPS is expected to have good application prospects in modern surgical medicine.

Impact of annealing on the characteristics of 3D-printed graphene-reinforced PLA composite

Manufacturing through additive techniques, especially utilizing the fused filament fabrication (FFF) method, is a transformative technology revolutionizing design and manufacturing. FFF builds parts layer by layer using thermoplastic polymer and polymer composite filaments. However, weak interlayer connections often lead to low interlaminar resistance in printed structures. Recent studies suggest that post-deposition heat treatments can mitigate this issue by reducing internal thermal stresses and enhancing layer adhesion, thereby improving part properties. This research delves into the impact of annealing heat treatment on a composite of Polylactic Acid (PLA) reinforced with graphene. The annealing process was conducted at temperatures of 90, 100, and 120 °C for durations of 60, 120, and 240 min. The annealing response of the graphene-reinforced PLA composite is compared to that of natural PLA for reference, analyzing its effects on electrical, thermal, chemical, and mechanical properties. Chemical characterization was performed using X-ray diffraction (XRD), Raman spectroscopy, and Fourier-transform infrared spectroscopy (FTIR). Thermal properties were analyzed via thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Electrical properties were assessed by measuring resistance, resistivity, and conductivity. Mechanical properties were evaluated through tensile, flexural, notch sensitivity, impact tests, and hardness measurements. The results demonstrated that annealing of graphene-reinforced PLA and natural PLA did not alter their functional groups but increased their crystallinity. This treatment improved thermal stability, electrical conductivity, and mechanical properties, including tensile strength, flexural strength, and Shore D hardness. However, it reduced impact and notch sensitivity resistances. The increased crystallinity had a greater beneficial impact on some properties than the graphene reinforcement. These findings have potential applications in the automotive, aerospace, electronics, and medical sectors, given the increasing use of PLA in these industries.

Investigating the Effects of Temperature, Azodicarbonamide, Boron Nitride, and Multilayer Film/Foam Coextrusion on the Properties of a Poly(Hydroxyalkanoate)/Poly(Lactic acid) Blend

Poly(hydroxyalkanoates) (PHAs) are emerging as sustainable materials in packaging and medical device industries. Nevertheless, the high cost and the need to improve the mechanical properties have limited their widespread use. Blending with other bio-based polymers, such as poly(lactic acid) (PLA), has been proposed in previous studies. This study investigates the effects of temperature, azodicarbonamide (AZ, foaming agent), boron nitride (BN, filler), and multilayer film/foam coextrusion on the properties of a blend containing an amorphous PHA and PLA. The effect of twin-screw micro-compounder temperature (185 °C & 205 °C) and BN concentrations of 1, 2, 3, 5, and 10 wt% (185 °C) on the properties of the PHA/PLA blend were investigated using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and tensile testing. Design of experiments (DoE) was used to find the optimal concentrations of AZ and BN (205 °C) using JMP® software. The response surface analysis predicted an optimal design based on the target response levels (modulus, tensile strength, strain at break, and toughness). This formulation was prepared and characterized using DSC, TGA, tensile, and melt flow index (MFI) measurements. Finally, this formulation was processed via film/foam coextrusion and examined using scanning electron microscopy (SEM) and density measurements. This study demonstrated that AZ and BN can be used to manipulate the mechanical properties and crystallinity of PHA/PLA blends, while reducing the overall material cost via density reduction (20–21% for the optimal formulation). Furthermore, reducing the concentration of AZ using the I-optimal design in this study could alleviate the toxicity concerns for food packaging.

Experimental Analysis of the Mechanical Characteristics of Vinyl Ester Composites Reinforced with Sisal Fiber for Prosthetic Socket

This research explores the scope of natural fibers for prosthetic socket application. A variety of conditions including maladies, accidents, and genetic disorders, necessitate the adoption of prosthetic organs. The human body undergoes significant physiological changes over time due to factors such as growth, weight fluctuations, and the periodic replacement and adjustment of appendages. In this study, biocomposite materials are fabricated using vacuum bag technology, with sisal fibers reinforced in vinyl ester at five different weight percentages: 0%, 5%, 10%, 15%, and 20%. Mechanical characteristics are determined through destructive testing, including flexural, tensile, impact strength, and hardness measurements according to ASTM standards. Scanning electron microscopy (SEM) analysis is employed to assess factrography and bonding properties. Results indicate that the biocomposite with 15% sisal reinforcement exhibited superior tensile and impact resistance compared to other compositions and matrices. However, at the expense of impact strength, the 20% sisal-reinforced vinyl ester increased hardness and flexural strength by 47% and 27%, respectively. This research aims to expand natural fibers and their utility in biomaterial applications, outlining points for elaboration and enhancement in this field, along with addressing associated challenges.

Tensile modulus measurement of composite materials based on distributed optical fiber strain monitoring technology

In this paper, a method was proposed to measure the elastic modulus of each layer-material in multi-layer cylindrical structures by OFDR in a large temperature range. Distributed measurement technology was used to carry out accurate measurements of strain distribution and numerical value on specimens. The accurate force-strain relationship can be obtained if the specimen is small or there is inevitable non-uniformity on the specimen. In this paper, a tensile test platform was built, and the tensile tests of optical fiber (−51.6 °C to 82.15 °C), polymer double-layer specimen (−54 °C to 63 °C), and composite three-layer specimen (−46 °C to 62 °C) were carried out. The elastic modulus of the three kinds of material and their relationships with temperature were obtained. By comparing with the standard test results, the accuracy and reliability of the test were verified.

Preparation and Structure-Property Relationship Study of Piezoelectric-Conductive Composite Polymer Nanofiber Materials for Bone Tissue Engineering.

This study aimed to develop Janus-, cross-network-, and coaxial-structured piezoelectric-conductive polymer nanofibers through electrospinning to mimic the piezoelectricity of bone and facilitate the conduction of electrical signals in bone tissue repair. These nanofibers were constructed using the piezoelectric polymer polyvinylidene fluoride, and the conductive fillers reduced graphene oxide and polypyrrole. The influence of structural features on the electroactivity of the fibers was also explored. The morphology and components of the various structural samples were characterized using SEM, TEM, and FTIR. The electroactivity of the materials was assessed with a quasi-static d33 meter and the four-probe method. The results revealed that the piezoelectric-conductive phases were successfully integrated. The Janus-structured nanofibers demonstrated the best electroactivity, with a piezoelectric constant d33 of 24.5 pC/N and conductivity of 6.78 × 10-2 S/m. The tensile tests and MIP measurements showed that all samples had porosity levels exceeding 70%. The tensile strength of the Janus and cross-network structures exceeded that of the periosteum (3-4 MPa), with average pore sizes of 1194.36 and 2264.46 nm, respectively. These properties indicated good mechanical performance, allowing material support while preventing fibroblast invasion. The CCK-8 and ALP tests indicated that the Janus-structured samples were biocompatible and significantly promoted the proliferation of MC3T3-E1 cells.

Reinforcing membranes with subgaskets in proton exchange membrane water electrolysis: A model-based analysis

Ensuring the long-term mechanical durability of perfluorosulfonic acid membranes in proton exchange membrane water electrolysis (PEMWE) is essential for long lifetimes. This study investigates the potential of reinforcing the membrane by incorporating a subgasket layer outside the active area. Thus, experimental tensile measurements with the subgasket material and with the subgasket-membrane composite are conducted to characterize their mechanical properties. The obtained data are used to identify suitable material models and parameterize them by applying a tensile test simulation based on the finite element method. By integrating subgaskets in a structural mechanics PEMWE cell model, the impact of the reinforcement on the membrane stability was investigated. The results indicate that even thin layers of subgaskets stabilize the membrane at the gap interface between the cell frame and the porous transport layer. The level of stabilization is further enhanced when using thicker subgaskets that cover the entire gap. However, one-sided subgaskets exhibit reduced mechanical stabilization. Furthermore, membrane buckling due to an increased gap size can be prevented using a subgasket up to a maximum gap size of 0.45 mm.

Microstructural, mechanical, thermo‐rheological, barrier, and antimicrobial properties of coextruded tri‐layer polylactide/encapsulated geraniol/polylactide‐graphene nanoplatelets films

AbstractA sustainable polylactide (PLA)‐based multilayer food packaging film was developed to improve neat PLA films' modest mechanical, thermal, and water/gas barrier properties. To improve the desired properties and impart antimicrobial aspects to the composite films, graphene nanoplatelets (GNP), and geraniol (GER) were reinforced into single‐layered PLA films. The project aimed to assemble three monolayers into multilayer films (MLF) through a coextrusion process, keeping the PLA‐GER layer in the core. X‐ray diffractograms, micrographs, and roughness parameters of the films demonstrated the dispersion of GNP in the film. Thermogravimetric analysis confirmed an enhancement in the thermal stability of the MLF by around 8°C when compared against single‐layer PLA films. An improvement in mechanical rigidity was supported by tensile (>87%) and rheological measurements. The polymers exhibit liquid‐like behavior in melts. Barrier properties did not improve for the MLF due to the agglomeration of GNP. The excellent antimicrobial properties of the MLFs for 3 weeks of storage at refrigerated conditions against both gram‐positive and gram‐negative pathogens were attributed to the release of GER from the film into the packed chicken samples and proved their potential for use in the food industry.

Evolution of Microstructure During Stress Relieving Heat Treatment of 1S Aluminium

Aluminium and its alloys are extensively used in nuclear research reactors due to its low neutron absorption coefficient, good heat transfer properties, excellent corrosion and oxidation resistance in air and water environment combined with desirable mechanical properties along with considerable radiation stability. The thin walled tubes are normally manufactured through port hole die extrusion route and used in 'O' tempered condition. The thin tubes in 'O' tempered condition are undergone canning operation which may alter the microstructural features to some extent which may affect mechanical properties. The paper describes the extent to which microstructural and subsequently mechanical properties are altered due to the simulated canning process and further requirements of stress relieving heat treatment to restore the microstructural features and mechanical properties. The following studies are carried out with 1S aluminum tube in 'O' tempered state, simulated canning condition and stress relieved at different temperature, - hardness measurement, X ray line profile analysis for dislocation density measurement, tensile properties measurement using ring tensile testing, electron back scattered diffraction (EBSD) analysis for recrystallization fraction determination and changes in texture components. It is found that the canning operation changes dislocation density, micro-strain, coherent domain size which are well reflected in hardness and ring tensile testing. Subsequent stress relieving at 350°C for 2 hrs. leads to improvement of mechanical properties appreciably.

Statistical evaluation of measured biomechanical properties of human brain aneurysm samples.

<p>Human brain aneurysms may often prove fatal if not re&shy;cognized in time and treated accordingly. The understanding of development and rupture of aneurysms can significantly be improved by the application of numerical modelling, which in turn, requires the knowledge of mechanical properties of vessel wall. This study aims to identify assumed differences with respect to age, sex, spatial orientation, and rupture by utilizing detailed statistical analysis of uniaxial tensile measurements of human brain aneurysm samples, performed by the authors in a previous project.</p>. <p>At surgery of 42 patients, aneu&shy;rysm fundi were cut distally to the clip. In each case, depending on size, varying number of stripes (altogether 88) were prepared and uniaxial stress-strain measurements were performed. Quantities related to the capacity, energy absorption or stiffness were determined and statistically analysed.</p>. <p>The number of specimens in the aneurysm sample was sufficient to establish statistical differences with respect to sex and rupture (p&lt;0.05). No significant differences were detected in orientation, though higher values of stresses and deformations were ob&shy;tained in the circumferential direction com&shy;pared to the meridional direction.&nbsp;</p>. <p>Significant differences bet&shy;ween sexes with respect to ultimate deformations were demonstrated according to expectation, and the hypothesis on equality of energy capacity could be supported. Similarity of curves with respect to specimen orientation was also observed and ruptured aneurysm sacs tended to be smaller in size. It seems that differences and trends described in this paper are realistic and need to be applied in numerical modelling.</p>.

Thermadapt shape memory vitrimeric polymyrcene elastomer

Earlier studies of β-Myrcene (Myr)/ β-ketoester functional (acetoacetoxy)ethyl methacrylate (AAEMA) copolymers exhibited compositional drift, leading to ambiguity in microstructure/thermomechanical property correlations while shape memory recovery times were excessively long ~1 h. The terpene-based 1,3-diene Myr and AAEMA were copolymerized via nitroxide-mediated polymerization (NMP) with an initial Myr molar feed ratio ranging from 0.1 to 0.9. Reactivity ratios estimated by the Meyer-Lowry method were rMyr = 0.20 and rAAEMA = 0.22 with respective 95% confidence intervals of [0.13, 0.37] and [0.15, 0.23], suggesting alternating copolymerization. Bulk terpolymerization with styrene (Sty) afforded linear poly(Myr-stat-Sty-stat-AAEMA) prepolymers designed to modulate glass transition temperature Tg and stiffness. Subsequent cross-linking with isophorone diamine (IPDA) formed catalyst-free vinylogous urethane dynamic linkages. ATR-FTIR, dynamic mechanical analysis (DMA), and tensile measurements confirmed the recyclability of vitrimers through hot pressing at 110 °C, demonstrating minimal changes in rheological and mechanical properties even after four cycles. By heating the vitrimers to above their Tg (to ~45 °C), they exhibited a shape memory effect with high shape fixity and fast shape recovery (< 1 min). The vitrimers could undergo permanent shape reprogramming through reconfiguration of dynamic bonds at ~110 °C. This work shows the adaptability of Myr-based rubbers by vitrification and appropriate copolymerization for the synthesis of more sustainable elastomers with stimuli responsive properties.

Chemical bonds and hair behaviour-A review.

When undertaking any review of the structure of the hair and its mechanical properties it becomes apparent that the overall behaviour of keratin fibres is commonly attributed to the presence of hydrogen, disulfide and ionic bonds. The action of physico-chemical agents used during various cosmetic treatments is viewed as the result of an interaction with these bonds. Thus, the breaking of bonds by chemical agents, or via mechanical or thermal stresses, affects the relative balance of disulfide and hydrogen bonds and the contribution of hydrophobic interactions, which are all important factors that may alter hair behaviour. Generally, these chemical bonds are considered as responding homogeneously to the environmental and cosmetic factors. This unitary image is challenged, however, by evaluating the results of chemical, nanomechanical, tensile and thermal measurements, which suggest that disulfide bonds may be grouped into several types, according to their location within the fibre and the way they respond to various agents. A compensatory effect of newly formed hydrogen bonds for broken disulfide bonds may also be seen, and additionally involves different types of hydrogen bonds. As a result, the picture of chemical bonding in hair appears to be far from a homogeneous one. In addition, it is apparent that further investigation is required for clarifying the action of ionic bonds and hydrophobic interactions within the hair fibre. The present review aims, thus, at offering a deeper background for understanding how the hair behaves under various conditions.

Microstructure, tensile strength, and hardness of AA5024 modified with ZrH4 additions produced by laser powder bed fusion

This work investigates the effect of ZrH4 additions on a commercial AA5024 aluminum alloy produced via Laser Powder Bed Fusion (L-PBF) where pre-mixed powders of AA5024 and ZrH4 were used. The microstructure was characterized using light and scanning electron microscopy assisted by energy-dispersive X-ray spectroscopy, and electron backscattered diffraction. The mechanical properties were evaluated by hardness and tensile measurements. The ZrH4 additions modify the microstructure. Regions without particles originate the large and elongated grains, while regions with undissolved ZrH4 or formed particles during solidification originate a fine equiaxed microstructure. The fine-grained region is typically located at the boundary of the melt pools, while the coarse-grained region is formed within the melt pools. There is substantial grain refinement with additions higher than 2.0 wt% ZrH4, nearly eliminating the coarse-grained region. The grain size does not differ in the fine-grained region for the different ZrH4, cross-sections (perpendicular or along the printing direction), or printing parameters. The 〈110〉 crystallographic fiber texture is identified, and a few particular texture components are more pronounced, such as the Cube {001} 〈100〉, the rotated Cube {001} 〈110〉, the Goss {011} 〈001〉, and Z {111} < 110>. Low texture index values are obtained in the fine-grained region, indicating the highly isotropic microstructure. The hardness and tensile strength increase with the increase in ZrH4 content for the as-built condition. A saturation in tensile strength is reached after 1.0 wt% ZrH4 additions.

Sonochemical synthesis of bioinspired graphene oxide–zinc oxide hydrogel for antibacterial painting on biodegradable polylactide film

Graphene oxide nanosheet (GO) is a multifunctional platform for binding with nanoparticles and stacking with two dimensional substrates. In this study, GO nanosheets were sonochemically decorated with zinc oxide nanoparticles (ZnO) and self-assembled into a hydrogel of GO–ZnO nanocomposite. The GO–ZnO hydrogel structure is a bioinspired approach for preserving graphene-based nanosheets from van der Waals stacking. X-ray diffraction analysis (XRD) showed that the sonochemical synthesis led to the formation of ZnO crystals on GO platforms. High water content (97.2%) of GO–ZnO hydrogel provided good property of ultrasonic dispersibility in water. Ultraviolet-visible spectroscopic analysis (UV–vis) revealed that optical band gap energy of ZnO nanoparticles (∼3.2 eV) GO–ZnO nanosheets (∼2.83 eV). Agar well diffusion tests presented effective antibacterial activities of GO–ZnO hydrogel against gram-negative bacteria (E. coli) and gram-positive bacteria (S. aureus). Especially, GO–ZnO hydrogel was directly used for brush painting on biodegradable polylactide (PLA) thin films. Graphene-based nanosheets with large surface area are key to van der Waals stacking and adhesion of GO–ZnO coating to the PLA substrate. The GO–ZnO/PLA films were characterized using photography, light transmittance spectroscopy, coating stability, scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopic mapping (EDS), antibacterial test and mechanical tensile measurement. Specifically, GO–ZnO coating on PLA substrate exhibited stability in aqueous food simulants for packaging application. GO–ZnO coating inhibited the infectious growth of E. coli biofilm. GO–ZnO/PLA films had strong tensile strength and elastic modulus. As a result, the investigation of antibacterial GO–ZnO hydrogel and GO–ZnO coating on PLA film is fundamental for sustainable development of packaging and biomedical applications.

Agricultural by-product filled poly(lactic acid) biocomposites with enhanced biodegradability: The effect of flax seed meal and rapeseed straw

The purpose of this research was to develop “green” materials by combining poly(lactic acid) (PLA) with two agricultural by-products, namely flax seed meal (FSM) and rapeseed straw (RSS). The natural fillers (0–20 wt.%) were mixed with PLA through extrusion and then injection molded into specimens. The samples were analyzed for their thermal, morphological, mechanical, and physical features and biodegradability. Thermal properties and crystallinity were analyzed using Differential Scanning Calorimetry (DSC), while the morphology was investigated by Scanning Electron Microscopy (SEM). Mechanical properties were characterized through tensile, flexural, and impact measurements, while surface hardness was evaluated by Shore D tests. Water absorption and biodegradability of the samples were also examined. DSC measurements revealed a nucleating effect of both bio-fillers. Based on the tensile tests, major improvement in stiffness was found with the biocomposites having up to ∼16 % higher Young's modulus than neat PLA (2.5 GPa). It came, however, at the cost of tensile strength, which decreased from 56 to 51 MPa even in the presence of the lowest amount (2.5 wt.%) of FSM. Loss in strength was due to the limited adhesion between the components, as also supported by SEM images. The hardness slightly (1–2 %) improved in the presence of even 2.5 wt.% bio-filler and it remained at that level at higher filler loading as well. Laboratory-scale composting revealed that both fillers facilitated biodegradation with FSM being superior. In the presence of 10–20 wt.% FSM, the rate of decomposition was found to be twice as fast compared to neat PLA.

Fabrication of photothermal responsive dual-chamber microcapsules for self-healing epoxy anticorrosion coatings

It has been urgent that timely repair of microdamage generated during long-term service of metal insulation coatings. Hereby, we developed a novel self-healing dual-chamber microcapsule with particle size about 5 μm, in which furfuryl amine modified polystyrene-acrylic acid (PSAF) as shell material and photosensitizer Carbon dots (CDs) as Pickering emulsifier. The synthesized materials were characterized analytically, FTIR and DSC demonstrated the simultaneously existence of healing agent and curing agent in the resultant dual-chamber microcapsule. Experiments also showed microcapsules exhibited satisfying storage stability more than 20 d at room temperature as well as thermogenesis effect that allowing temperature of epoxy composite materials raised to 50 °C in 60s and fractures to be effectively minimized in time. The scratch tensile measurement results demonstrated that epoxy resin composites incorporated with 2 wt% microcapsules exhibited the optimal strength self-healing efficiency, modulus, toughness and anti-fatigue performance. Furthermore, surface characterization and EIS analysis also confirmed the long-lasting healing effect of EP/MC2% complex coating with outstanding corrosion resistance. Therefore, the photothermal responsive dual-chamber microcapsule designed in this work has application as self-healing material especially epoxy anti-corrosion coating.