Effect of peanut shell content on mechanical,thermal, and biodegradable properties of peanut shell/polylactic acid biocomposites

Peanut shell (PNS) was combined with polylactic acid (PLA) to form biocomposites. The biocomposites, with up to 40 wt% PNS, were prepared using a twin–screw extruder. The effect of PNS content on the thermal, mechanical, thermomechanical, morphological, and biodegradable properties was studied. The results showed that the addition of PNS caused a reduction of the melting temperature and the decomposition temperature. Furthermore, the crystallinity of the biocomposites slightly increased with increasing PNS up to 30 wt%. The morphological study showed poor interfacial adhesion between the PNS and PLA matrix. Nevertheless, the mechanical properties revealed that the maximum tensile strength and Young's modulus were at a 30 wt% PNS loading and decreased as more PNS was incorporated into the PLA matrix. The impact strength decreased with an increase in PNS content. The addition of PNS showed significantly improvement of the storage modulus of PLA at high temperature (>80°C). Moreover, the presence of PNS enhanced the biodegradability of the biocomposites. POLYM. COMPOS., 38:682–690, 2017. © 2015 Society of Plastics Engineers     

Properties of coconut shell powder‐filled polylactic acid ecocomposites: Effect of maleic acid

Ecocomposites were produced by incorporating coconut shell powder (CSP) into polylactic acid (PLA) resin. The effect of filler content and chemical modification on the mechanical properties, thermal properties, and morphology of PLA/CSP ecocomposites were investigated. The addition of filler has decreased the tensile strength and elongation at break of PLA/CSP ecocomposites. However, tensile strength and modulus of elasticity of PLA/CSP ecocomposites were enhanced by maleic acid treatment. Meanwhile, glass transition temperature (T_g) and crystallinity (X_c) of PLA/CSP ecocomposites increased at 30 php of filler content and increased the presence of maleic acid (MA). However, the melting temperature (T_m) and crystallization temperature (T_c) were not significantly changed with the filler content and MA modification The thermal stability of PLA/CSP ecocomposites increased with the CSP content. The MA modification improved the thermal stability of PLA/CSP ecocomposites through better filler–matrix interaction. The improvement was confirmed by scanning electron microscope study. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers     

Effect of coupling agent content on properties of composites made from polylactic acid and chrysanthemum waste

Chrysanthemum flower is among one of the highly sought after and widely planted flower crops, in particular for cultural and religious ceremonies. However, the chrysanthemum stem and stalk have little value and usually discard as by‐product waste from floristry. The objective of this research is to investigate the potential value of utilizing chrysanthemum stem and stalk as reinforcing fillers for thermoplastic composites. In this study, 2‐mm thick composite sheet containing predefined formulations of polylactic acid (PLA), chrysanthemum waste filler (CWF) ranging from 15 to 60 phr, and maleated polyethylene (MAPE) coupling agent up to 5 phr were prepared with the aid of Haake internal mixer and compression molding. The effect of MAPE loading on tensile, thermal, and morphological properties of PLA/CWF composites was investigated. The findings revealed that PLA/CWF composite attained improved tensile modulus compared to the neat PLA, and the tensile modulus increases with higher concentration of CWF. However, both tensile strength and elongation at break reduces with increase loading of CWF. Overall, PLA/CWF composites with MAPE shows better performance compared to those without MAPE, where an optimum strength of 21.8 MPa can be achieved with 60 phr CW and 3 phr MAPE. The measured tensile strength is comparable to alternatives natural fiber thermoplastic composites demonstrating its potential to be used in non‐structurally demanding application. J. VINYL ADDIT. TECHNOL., 26:10–16, 2020. © 2019 Society of Plastics Engineers     

Mechanical and thermal properties of low density polyethylene composites filled with dye‐loaded shell powder

To achieve reinforcement and coloring in one combined process of polymer production, a dye‐loaded shell powder (DPSP) based on Congo red and pearl shell powder was prepared and used as a versatile bio‐filler in low‐density polyethylene (LDPE). The DPSP was characterized by means of X‐ray diffraction, Fourier transform infrared spectroscopy and thermogravimetric analysis. The mechanical, thermal, and colorimetric properties of prepared LDPE/DPSP composites were investigated as well. Adding DPSP could significantly increase the strength and stiffness of LDPE composites while giving an outstanding coloring performance. Moreover, the impact strength of LDPE composites was improved at lower filler loading rate, and the maximum incorporation content could reach 10 wt % with a good balance between toughness and stiffness of LDPE composites. The thermal performance studies confirmed an increase in thermal stability and heat resistance of LDPE composites with the incorporation of DPSP. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44118.     

Effect of silane coupling agent on the dielectric and thermal properties of DGEBA-forsterite composites

Diglycidyl ether of bisphenol A (DGEBA) -forsterite composites have been prepared through mechanical mixing process and the influence of silane coupling agent on the microstructure, dielectric and thermal properties were studied. Phase pure forsterite (Mg₂SiO₄) powder was prepared through solid state ceramic route. Filling fraction of forsterite in DGEBA matrix was varied from 10 to 40 vol%. The morphology and filler distribution of filled composite were studied by Scanning Electron Microscopy. Waveguide cavity perturbation technique was employed to measure the dielectric properties of composites. It is found that aminosilane treatment increased the dielectric constant and dielectric loss of the composites in both microwave and radio frequency ranges compared to composites prepared using untreated powders. Coefficient of thermal expansion of composites decreased with the forsterite addition and attains a relatively low value of 45 ppm/°C for composite containing 40 vol% surface treated filler.     

Effect of filler loading and coconut oil coupling agent on properties of low‐density polyethylene and palm kernel shell eco‐composites

Palm kernel shell (PKS), a waste from the oil palm industry, has been utilized as filler in low‐density polyethylene (LDPE) eco‐composites in the present work. The effect of PKS content and coconut oil coupling agent (COCA) on tensile properties, water absorption, and morphological and thermal properties of LDPE/PKS eco‐composites was investigated. The results show the increase of PKS content decreased the tensile strength and elongation at break, but increased the tensile modulus, crystallinity, and water absorption of eco‐composites. The presence of COCA as coupling agent improved the filler‐matrix adhesion yield to increase the tensile strength, tensile modulus, crystallinity, and reduced water absorption of eco‐composites. The better interfacial adhesion between PKS and LDPE with the addition of COCA was also evidenced by scanning electron microscopy studies. J. VINYL ADDIT. TECHNOL., 22:200–205, 2016. © 2014 Society of Plastics Engineers     

Curing characteristics and mechanical properties of rattan‐powder‐filled natural rubber composites as a function of filler loading and silane coupling agent

Curing characteristics, tensile properties, morphological studies of tensile fractured surfaces using scanning electron microscopy (SEM), and the extent of rubber filler interactions of rattan‐powder‐filled natural rubber (NR) composites were investigated as a function of filler loading and silane coupling agent (CA). NR composites were prepared by the incorporation of rattan powder at filler loading range of 0–30 phr into a NR matrix with a laboratory size two roll mill. The results indicate that in the presence of silane CA, scorch time (t_s2), and cure time (t₉₀) of rattan‐powder‐filled NR composites were shorten, while, maximum torque (M_H) increased compared with NR composites without silane CA. Tensile strength and tensile modulus of composites were enhanced whereas elongation at break reduced in the presence of silane CA mainly due to increase in rubber‐filler interaction. It is proven by SEM studies that the bonding between the filler and rubber matrix has improved. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

硅烷偶联剂改性炭黑-白炭黑双相粒子对天然橡胶物理机械性能的影响

用硅烷偶联剂（Si 69）改性炭黑-白炭黑双相粒子（CSDPF）,研究了CSDPF的改性及用量对天然橡胶（NR）物理机械性能及填料-橡胶相互作用的影响。结果表明,随着CSDPF或改性CSDPF（mCSDPF）用量的增加,所填充硫化胶的物理机械性能均有所提高。在填充量相同的情况下,mCSDPF/NR硫化胶的物理机械性能更好。填充量为60份（质量,下同）时,与CSDPF/NR硫化胶相比,mCSDPF/NR硫化胶的拉伸强度增加14.57%,疲劳寿命提高40.74%,磨耗体积减小10.00%;填充量为40份时撕裂强度提高32.11%。mCSDPF与NR之间的相互作用更强。     

Mechanical and thermal properties of biocomposites from poly(lactic acid) and DDGS

Distillers dried grains with solubles (DDGS), an ethanol industry coproduct, is used mainly as a low‐value feedstuff. Poly(lactic acid) (PLA) is a leading biodegradable polymer, but its applications are limited by its relatively high cost. In this study, low‐cost, high‐performance biodegradable composites were prepared through thermal compounding of DDGS and PLA with methylene diphenyl diisocyanate (MDI) as a coupling agent. Mechanical, morphological, and thermal properties of the composites were studied. The coupling mechanism of MDI in the PLA/DDGS system was confirmed via Fourier‐transform infrared spectra. The PLA/20% DDGS composite with 1% MDI showed tensile strength (77 MPa) similar to that of pure PLA, but its Young's modulus was 25% higher than that of pure PLA. With MDI, strong interfacial adhesion was established between the PLA matrix and DDGS particles, and the porosity of the composites decreased dramatically. Crystallinity of PLA in the composites was higher than that in pure PLA. Composites with MDI had higher storage moduli at room temperature than pure PLA. This novel application of DDGS for biocomposites has significantly higher economic value than its traditional use as a feedstuff. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Effect of surface oxidation of filler and silane coupling agent on the chemorheological behavior of epoxidized natural rubber filled with ISAF carbon black

On the basis of results of measurements of physical properties and solvent swelling of the extrudates, it has been observed that epoxidized natural rubber (ENR) interacts chemically with intermediate super abrasion furnace (ISAF) carbon black when the mix of the two was extruded at 130–160°C in a Monsanto Processability Tester (MPT). The extent of interaction between the rubber and filler depends on the following factors: extrusion time, carbon black loading, shear rate, and the extent of oxidation on the carbon black surface. Addition of the silane coupling agent, namely, N‐3‐(‐N‐vinyl benzyl amino) ethyl‐γ‐amino propyl trimethoxy silane monohydrochloride, enhances the rate of the interaction. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 557–563, 1999     

Influence of silane‐modified coconut shell powder on thermal and mechanical properties of thermoplastic elastomers

A silane coupling agent (glycidyloxypropyltrimethoxysilane, GPTMS) was used to modify coconut shell powder (CSP), and the influence of the modified coconut shell powder (G‐CSP) on the thermal and mechanical properties of thermoplastic elastomers (TPEs) was investigated. The thermal stabilities of the G‐CSP‐TPEs were studied using TGA; Young's modulus of the G‐CSP‐TPEs was studied by means of the spherical indentation test and the tensile test, and the tensile test was also used to characterize the tensile strength of the G‐CSP‐TPEs. The results revealed that the specific functional groups of GPTMS were efficiently grafted onto the CSP and that G‐CSP enhanced the thermal stability of the TPEs. Under 8% strain, Young's moduli of 0–7.5 wt% G‐CSP‐TPEs obtained by the spherical indentation test and tensile test were almost equal, while the modulus of 10–15 wt% G‐CSP‐TPEs measured by the latter test was greater than that of the former test. The tensile strength of G‐CSP‐TPEs increased up to a threshold limit (10 wt% G‐CSP), followed by a significant decrease. Micro‐images of the fractured surfaces obtained by SEM indicated that the addition of G‐CSP gradually filled the microvoids in the matrix and enhanced the tensile strength of the composite. As the G‐CSP mass percentage exceeded a threshold limit (>10 wt%), the particles started to agglomerate, resulting in weak interfacial adhesion and inferior mechanical properties. Hence, an optimal amount of reinforcing agent G‐CSP should be added to attain desirable thermal and mechanical properties. © 2020 Society of Chemical Industry     

Effect of thermal annealing on the mechanical and thermal properties of polylactic acid–cellulosic fiber biocomposites

Polylactic acid (PLA) biocomposites were produced by a combination of extrusion and injection molding with three cellulosic reinforcements (agave, coir, and pine) and contents (10, 20, and 30%). In particular, some samples were subjected to thermal annealing (105 °C for 1 h) to modify the crystallinity of the materials. In all cases, morphological (scanning electron microscopy) and thermal (differential scanning calorimetry, dynamical mechanical thermal analysis) characterizations were related to the mechanical properties (Charpy impact, tensile and flexural tests). The results showed that annealing increased the crystallinity for all the materials produced, but different mechanical behaviors were observed depending on fiber type and content. For example, annealing increased the impact strength and flexural modulus of PLA and PLA biocomposites (agave, coir, and pine), while decreasing their flexural strength. But the main conclusion is that fiber addition combined with thermal annealing can substantially increase the thermal stability of the studied materials. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43750.     

Effect of coupling agent on polylactic acid/polypropylene and polylactic acid/polyamide 6 foam composites

The main part of polymer materials generated from fossil fuels do not degrade after completing their usage life and then begin to be waste in the environment. This situation has led to the emphasis on environmentally friendly, biodegradable, and bio-based polymers obtained from renewable sources as an alternative. In recent years, several studies are concentrated on especially lightweight and carbon dioxide (CO₂) emission limitations. In this work, the goal was to investigate at the same time environmentally friendly and lightweight polymer foam composites based on polylactic acid (PLA) polymer without lowering the performances of the materials. In this aim, polymer foam composites containing polypropylene (PP), polyamide 6 (PA6) and PLA were produced (PLA/PA6 (30:70) and PLA/PP (30:70)) with a chemical blowing agent (CBA) introduced at 1.5 wt.% to the polymer mixture. To improve the interpolymer compatibility and foaming activity maleic anhydride-grafted polylactic acid (PLA-g-MA) was utilized as coupling agent (CA) in different ratios (1, 3 and 5 wt.%). From the evaluation of the polymer mixtures in terms of their lightness, thermal and mechanical strength, the most appropriate CA ratios were determined as 1 wt.% for foamed PLA/PP (30:70) mixtures and 3 wt.% for foamed PLA/PA6 (30:70) mixtures.     

Mechanical properties of surface‐treated banana fiber/polylactic acid biocomposites: A comparative study of theoretical and experimental values

Current study evaluates the effect of fiber surface treatments on the mechanical properties of banana fiber (BF) reinforced polylactic acid (PLA) biocomposites. Experimental results indicate increase in tensile modulus and strength upon surface treatments of BF with various silanes (APS and Si69) and NaOH. Approximately, an increase of 136% in tensile strength and 49% in impact strength was obtained in case of biocomposites with Si69‐treated BF compared with the untreated BF biocomposites. Also, experimentally determined mechanical modulus of untreated and surface‐treated BF biocomposite has been compared with the mechanical modulus calculated using various micromechanical models. Models such as Hirsch's, modified Bawyer and Bader's, and Brodnyan model showed good agreement with the experimentally determined results. Similarly, other models like Halpin‐Tsai, Nielson modified Halpin‐Tsai, and Cox's model also have been tried for the comparative study with the experimental data. Surface modification of BF showed increased interfacial adhesion between the fiber and the matrix which was evident from lowered difference between the experimentally and theoretically derived mechanical modulus. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Effect of silane coupling agent on the structure and mechanical properties of nano‐dispersed clay filled styrene butadiene rubber

In rubber nanocomposites containing inorganic clay, the reinforcement effect has always been relatively insignificant due to the poor interfacial interaction between the rubber matrix and clay fillers. In this work, the silane coupling agent bis[3‐(triethoxysilyl)propyl]tetrasulfide (Si‐69) was employed through mechanically blending with styrene butadiene rubber (SBR)/clay (100/30) nanocompound that was prepared by combined latex compounding and spray‐drying technique, to serve as the molecular bridge between SBR matrix and clay filler and strengthen the interfacial interaction. TEM and XRD characterization indicated that Si‐69 significantly improved the dispersion of the silicate layers in the SBR matrix. The RPA analysis and the mechanical property study of the SBR/clay nanocomposites revealed that the filler network interaction was weakened while the filler–rubber interaction was strengthened upon the addition of Si‐69. POLYM. COMPOS., 37:890–896, 2016. © 2014 Society of Plastics Engineers     

Effect of core–shell acrylate rubber particles on the thermomechanical and physical properties of biocomposites from polylactic acid and olive solid waste

Biocomposites from polylactic acid (PLA) and olive solid waste (OSW) were melt‐blended with core–shell acrylate rubber particles (ACR) in order to enhance the thermal stability upon melt processing and the mechanical performances of these biocomposites, thereby expanding their area of application. Dynamic mechanical analysis indicated that the ACR particles imparted more flexibility to the PLA/OSW biocomposites and thermal analysis showed that the incorporation of ACR significantly restrained the ability of the PLA chains to crystallize. The values of complex viscosity and storage modulus were significantly increased with the introduction of ACR. These results could be assigned to the entanglements between the PLA chains and those of the ACR shell, giving rise to a physical network that limited the segmental mobility of PLA and induced a high melt elasticity. Mechanical tests revealed that the elongation at break and the impact strength of the biocomposites were considerably improved. Moreover, morphological observations showed a clear adhesion enhancement between the PLA matrix and the OSW fillers in the presence of the ACR additive. POLYM. ENG. SCI., 58:894–902, 2018. © 2017 Society of Plastics Engineers     

Mechanical,thermal, and structural properties of uniaxially drawn polylactic acid/halloysite nanocomposites

The effect of solid-state drawing at different conditions including drawing ratio (DR), drawing temperature (DT), and drawing speed (DS) on mechanical, thermal, and structural properties of polylactic acid (PLA)/halloysite nanotubes (HNTs) composites were studied. PLA/HNTs composite films were prepared by melt mixing process followed by compression molding. Subsequently, drawing was performed using a tensile testing machine. Field emission scanning electron microscopy confirmed alignment and orientation of polymer chains and HNTs after stretching. Thermal and mechanical analysis of the drawn films revealed that glass transition temperature, crystallinity, ultimate tensile strength, and Young's modulus were enhanced by increasing DR, DT, and DS. However, toughness was decreased by increasing DR and DS and increased by increasing DT. In addition, the drawn nanocomposites showed superior mechanical and thermal properties compared to the drawn neat PLA films indicating the high efficiency of solid-state drawing and positive effect of HNTs. Therefore, this study could be helpful to introduce an approach to enhance the properties of biopolymers and renewable polymers by uniaxial drawing.     

硅烷偶联剂对炭黑/白炭黑增强丁腈橡胶填料网络结构及动态性能的影响

研究了硅烷偶联剂种类及其并用对炭黑/白炭黑增强丁腈橡胶(NBR)填料网络结构及动态性能的影响.结果表明,硅烷偶联剂双-[γ-(三乙氧基硅)丙基]四硫化物(Si 69)能有效降低炭黑/白炭黑增强NBR混炼胶的Payne效应,促进填料在橡胶基体中的分散,而硅烷偶联剂3-氨丙基三乙氧基硅烷(KH 550)或其与Si 69并用...     

Some interesting phenomena in silica‐filled HNBR with the addition of silane coupling agent

Hydrogenated nitrile rubber (HNBR)/silica nanocomposites were prepared by in‐situ modification dispersion technology, and the silane coupling agent γ‐methacryloxypropyl trimethoxy silane (KH570) was chosen to promote the interfacial strength between silica particles and HNBR matrix and further improve the dispersion of silica particles. Rubber Process Analyzer (RPA2000) was used to test the Payne effect of HNBR/silica compounds, from which some interesting phenomena were found: the Payne effect became stronger after KH570 was added to HNBR/silica compound at room temperature, which was a contrary result compared to SBR/silica system. However, after stored for a month at room temperature, the Payne effect weakened, which was contrary to the traditional phenomenon of storage hardening of filled rubber. All these results are related to filler–filler interaction and filler–rubber interaction. The modulus at small strain amplitude of HNBR/silica compound with KH570 gradually decreased with the increase of times of circulatory strain sweep but that of compound without KH570 had almost no change, which was explained by Fourier Transform Infrared (FTIR) results that the reaction between silica and KH570 almost completed at the test condition: 80°C and about 1 h. The effects of silane amount, heat‐treated temperature and time on the Payne effect of compounds and the mechanical properties of vulcanizates were also investigated. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Effect of silane coupling agent on filler and rubber interaction of silica reinforced solution styrene butadiene rubber

In the present article, the influence of bis‐(triethoxysilylpropyl)‐tetrasulfide (TESPT) content on the viscoelastic behavior of silica filled Solution Styrene Butadiene Rubber (SSBR) was carefully studied in terms of loss tangent spectrum and bound rubber content. The results showed that both relative tan δ area and tan δ_max of filled SSBR with TESPT were detected to present maximum value at 2.5 wt% TESPT(with respect to silica loading). Larger tan δ area and tan δ_max meant more chains participating in the glass transition in the present system, which is reflected by the variation of effective filler volume with TESPT content. The interaction between filler and rubber can be improved remarkably when a little amount of TESPT up to 2.5 wt% was incorporated, whereas as the TESPT content exceeds 2.5 wt% the filler–rubber interaction was weakened, which was also proven by TEM images and Payne effect. The bound rubber content of this SSBR system studied presents the same tendency as tan δ_max. Once TESPT linked with rubber chains, the condensation reaction between silica and SCA is somewhat hindered because of the difficulty in diffusion of large molecules after SCA is chemically bonded with rubber molecules. The network structure of the filled SSBR was analyzed by applying elasticity model. The consecutive increase of crosslink density compensated the reduction of topological tube‐like constrains and thus tensile strength continued to ascend with TESPT content, but sacrificed the ultimate strain. POLYM. COMPOS., 34:1575–1582, 2013. © 2013 Society of Plastics Engineers