Studying the Influence of some Technological Factors on the Properties of Nitrocellulose-cellulose Material Sheets

Mulch was prepared using composted sugarcane leaves, with polyvinyl alcohol and cationic starch as adhesives, through compression molding. The study aimed to investigate the effects of different adhesives on the mechanical properties, thermal oxidative degradation performance, and biodegradability of the covering materials. The results indicated that, when the adhesive dosage was consistent, cover material A, which utilized polyvinyl alcohol as the adhesive, exhibited higher tensile strength and elongation at break compared to cover material B, which employed a blend of polyvinyl alcohol and cationic starch. Specifically, at an adhesive dosage of 20%, cover material A achieved a tensile strength of 0.46 MPa and an elongation at break of 7.72%, representing the highest values among all experimental groups. There was minimal disparity in the thermal oxidative degradation performance between materials prepared with either adhesive; however, a higher quantity of adhesive led to decreased biodegradability performance. After being buried in soil for 120 days, the degradation exceeded 40% for both materials, resulting in loss of their original shape and strength properties. In conclusion, while sugarcane leaves-based biodegradable materials demonstrate favorable degradation performance, further enhancements are necessary to improve their mechanical properties. These materials have potential applications as substitutes for plastic mulch.

Light-weight paper products that contain less fibres, but with a maintained bulk and improved strength properties, are highly desirable due to the low cost of raw materials and improved logistics of packaged goods. In this respect, the adsorption capacity of dry strength additives onto fibres, which is affected by the surface charge of said fibres, is very important for the development of these mechanically robust paper products. The influence of the surface charge on the adsorption of strength additives was investigated for, dissolving grade fibres, kraft fibres and kraft fibres modified with carboxymethyl cellulose (CMC) with different surface charge densities, but the same fibre dimensions. The strength additives investigated were cationic starch (CS), anionic polyacrylamide (APAM) and polyelectrolyte complexes (PECs), containing CS and APAM. A linear relationship was found between the surface charge of the fibres and the saturated adsorbed amount of CS. However, when either APAM or PECs adsorbed as secondary layers onto the CS, no correlation between cellulose charge and the saturation adsorption could be observed. The adsorption of APAM was dramatically affected by the pre-adsorbed amount of CS, whereas PECs were less influenced. Moreover, the additives improved the tensile strength (60%) and strain at break (> 100%) of handsheets formed with the kraft fibres and adsorbed APAM. It was also found that CS/APAM increased the sheet density while CS/PECs lowered it. In conclusion, the gained fundamental understanding of these adsorption of additives is of significant importance to facilitate the industrial development of sustainable low-cost high-end packaging products.Graphical abstract

در تحقیق حاضر بمنظور بهبود خواص فیزیکی و مکانیکی فیلم‌های زیست تخریب‌پذیر خوراکی ترکیب کردن دو پلیمر کربوکسی‌متیل‌سلولز (CMC) و کتیرا مورد مطالعه قرار گرفت. کربوکسی‌متیل‌سلولز و کتیرا با نسبت‌های 25:75، 50:50 و 75:25 با یکدیگر ترکیب شده و میزان نفوذپذیری به بخار آب، درصد حلالیت، خواص مکانیکی و ریزساختار آنها ارزیابی گردید. نتایج نشان داد که در میان سه نسبت مرکب دو پلیمر، میزان استحکام کششی در نسبت 50:50 نسبت به دو ترکیب دیگر بیشتر بود طوری که مقدار آن در نسبت های 50:50، 25:75 و 75:25، به ترتیب 59/44، 82/32 و 59/26 مگاپاسکال بوده است. نفوذپذیری به بخار آب در ترکیب 50:50 و 75:25 نسبت به ترکیب 25:75 از شرایط بهتری برخوردار بود. ویژگی حلالیت در آب در سه فیلم ترکیبی تفاوتی با یکدیگر نداشتند ولیکن دارای کیفیت بهتری نسبت به فیلم خالص CMC بودند طوری که مقدار 52 الی 58 درصد نسبت به فیلم خالص CMC کاهش معنی‌داری را در میزان حلالیت به نمایش گذاشتند. همچنین، ترکیب کردن دو پلیمر در نسبت‌های مختلف توانست از میزان حساسیت فیلم‌ها نسبت به رطوبت بکاهد. بطورکلی، از نتایج این تحقیق دریافت می شود که ترکیب کردن دو پلیمر می تواند برخی ویژگی‌های فیزیکی- مکانیکی فیلم خوراکی تهیه شده از کربوکسی‌متیل‌سلولز- کتیرا را بهبود بخشد.

The analogue materials play a critical role in dynamically scaled experiments, defining the processes that can be simulated and the structures observable in the model. The dynamic scaling enables the direct comparison between the model and its natural counterpart. To obtain such a model the physical and mechanical properties of the analogue material must be scaled with respect to the rock prototype. A large variety of materials have been applied in analogue modelling studies to address the physical and mechanical requirements for the simulation of (i) upper crust, (ii) middle crust and (iii) lower crust and mantle processes. Nevertheless, the development of new model materials represents a continuous improvement of the analogue modelling techniques.We investigated the mechanical and physical properties of a new Granular Rock-Analogue Material (GRAM) (introduced in Massaro et al. (2022)) and its component materials. GRAM is an ultra-weak artificial sandstone composed of quartz sand cemented with gypsum, capable to deform by tensile and shear failure under variable stress conditions. GRAM aggregates in different mixing ratios (from 1% to 4% in weight of hemihydrate powder) were systematically tested with ring-shear tests and uniaxial compression tests. The relationships between the hemihydrate content and the mechanical properties of GRAM were examined. Additionally, the sample preparation procedure of GRAM was investigated, evaluating the impact of the residual water content on the mechanical properties of GRAM aggregates and defining a standard preparation procedure. Finally, GRAM was compared to natural rocks and to other granular materials applied in analogue modelling studies, in terms of physical and mechanical properties, application to physical modelling and dynamic scaling. It was underlined how the application of GRAM aggregates in dynamically scaled experiments can enhance the comprehension of the fault and fracture processes occurring at the scale of the damage zone.

In the present study, attempts were made to manufacture innovative conducting polymer nanocomposites (CPCs) with high performance, low cost, and appropriate electrical, mechanical, and thermal properties. However, one of the main challenges in creating CPCs is the tendency of nanofillers to agglomerate and accumulate, resulting in a decrease in the electrical properties and performance of CPCs. To address this issue, the study developed an efficient and eco‐friendly CPC using carboxymethyl cellulose (CMC) as a binder and carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs) as nanofillers. The study employed a chemical functionalization method to modify CNTs and enhance their compatibility and dispersion properties in the CMC matrix. The prepared CPCs were characterized using various techniques, including Fourier‐transform infrared spectroscopy, x‐ray diffraction, and field emission scanning electron microscopy. The results showed an improvement in homogeneity and surface cohesion between CMC and O‐CNTs through chemical surface modification of CNTs via carboxylic acid functional groups. The study observed good dispersion of nanofillers without any aggregation of the CMC/GNP/O‐CNT compared with the nontreated CMC/GNP/CNT composite. While a decrease in the degree of crystallinity was observed, conductivity increased for the CPC containing oxidized CNTs. The study found that the highest conductivity of ~112 S/m was obtained for D‐CMC/GNP/O‐CNT with 25 wt% of O‐CNT, while the maximum conductivity of D‐CMC/GNP/CNT was ~80 S/m with 35 wt% of CNTs. Additionally, the study observed an improvement in electrochemical properties after treatment of CNTs in the form of higher cathodic current in cyclic voltammetry and lower charge transfer resistance in impedance spectroscopy of D‐CMC/GNP/O‐CNT35 compared to untreated one. Highlights Preparation of new conductive nanocomposite consisting of CMC, CNTs, and GNPs. Carboxylation of CNTs to improve O‐CNT and CMC intermolecular interaction CMC/GNP/O‐CNT is 40% more conductive than unmodified CNT nanocomposite. Higher thermal stability and mechanical properties were observed by using O‐CNT. O‐CNT caused higher current density and lower electron transfer resistance for CPCs.

Micro–macro characterisation of DGEBA-based epoxies as a preliminary to polymer interphase modelling

Effect of activated carbon on the properties of carboxymethylcellulose/activated carbon hybrid hydrogels synthesized by γ-radiation technique

The aim of this work was to study the relationship of chain size of partially hydrolyzed PVA blended with starch in properties of biodegradable sheets produced by thermoplastic extrusion. It was also studied the effect of extrusion temperature profile to determine the better PVA chain size and temperature profile to produce biodegradable sheets through a factorial design. The processability and the mechanical, thermal, optical, and microstructural properties of the biodegradable sheets were adequate, indicating that PVA/cassava starch blends have potential to replace conventional non-biodegradable polymers. Tensile strength and Young’s modulus ranges from 1.0 to 2.6 and 3.0 to 6.9 MPa respectively, the elongation at break ranges from 42 to 421%. It was not possible to state a conclusive relationship between PVA molecular weight and the materials properties, but in general, PVA with medium molecular weight and high extrusion temperature profile promote an increase of mechanical properties of the sheets.

In recent years, one of the main challenges is to improve the mechanical performance of bio-composites to be used as structural parts for the construction, automotive, and aviation sector. This paper may contribute to developing durable structural bio-composite parts with starch addition. The mechanical properties of bio-composites reinforced by eucalyptus or pine fibers (48 wt %) compound with Cationic Starch (48 wt %) and Carboxymethyl cellulose (CMC) (4 wt %) were determined. The production method was a combination of molded pulp, extrusion, and compression molding production techniques. To see the effect of adding starch to bio-composites and different production methods, the mechanical performance of these natural fibers produced by the conventional molded pulp production method (without any additives) was also found and compared with the composite samples. Composite samples indicate significantly better tensile, flexural, and compressive values, at least four times, compared with the molded pulp samples. On the other hand, the molded pulp samples had more than 2 times better impact characteristics against composites. Using molded pulp technic in composite production (investigated in the study) is a new idea and may give some opportunities with its serial production compatibility and geometry freeness, to the industry.

As a new kind of propellant binder, energetic thermoplastic elastomer ( ETPE ) can improve propellant recyclability and environmentally friendly disposal. The rheological behavior of the ETPE binder can be beneficial to identify suitable and safe conditions for processing ETPE propellants. In this paper, ETPE /nitrocellulose ( NC ) blends with different mass ratios of NC to ETPE were prepared by the physical mixing method. The heat of explosion and the morphological, thermal, mechanical and rheological properties of the resulting blends were studied systematically. It was found that the heat of explosion of ETPE / NC blends increased with increasing NC content. SEM images showed that the NC domains in the blends changed from tiny pieces to fibers with increasing NC mass ratio, which indicates phase separation in the blends. The tensile mechanical properties of the blends had a peak value when the NC content was 10 wt%, and then increased with the increasing addition of NC . The thermal behavior made clear that the ETPE and NC were partially miscible. Rheological studies on dynamic strain sweep and frequency sweep demonstrated that the content of NC in the blends had a monotonic effect on their rheological properties at 130 °C. Rheological studies also showed that the rheology of the blends is dependent on temperature. The Cole − Cole and Han plots confirmed phase separation in the blends. © 2016 Society of Chemical Industry

Carboxymethyl cellulose (CMC) bioplastic shows great promise for sustainable food packaging. This study synthesized zinc oxide nanoparticles (ZnO NPs) from pineapple waste via green synthesis and incorporated them into CMC to develop enhanced nanocomposite films. Key steps included preparing ZnONP powder and formulating ZnONP‐CMC (ZCMC) (1.0% w/v) solutions for film fabrication. The nanocomposites were characterized using FTIR, XRD, SEM–EDX, TGA, and DSC to assess structural integrity and thermal stability. Physical properties showed enhancement, including a thickness of 0.17.05 mm, opacity of 17%, moisture content of 52.38%, and water solubility of 64.52%. The mechanical properties also improved significantly, with a tensile strength of 26.30 MPa and elongation at a break of ∼50%. FTIR and XRD confirmed the successful incorporation of ZnO NPs, which improved the crystallinity and structural integrity of the CMC matrix. Notably, the ZCMC nanocomposite exhibited rapid biodegradation within 9 days under soil conditions, highlighting its potential for reducing environmental impact. In conclusion, adding ZnO NPs to CMC films notably improves their physical, mechanical, and thermal characteristics, rendering them ideal for food packaging. While the mechanical and biodegradation properties are promising for food packaging applications, future research should focus on evaluating the antimicrobial properties and practical applications of the ZCMC films in food preservation.

PurposeThree-dimensional bioprinting (3D bioprinting) is used for repairing and regenerating living tissues due to its ease of use, cost-effectiveness and high precision in fabricating. Owing to their high biocompatibility, natural hydrogels are widely used as scaffold materials in bioprinting. However, the mechanical properties and low printability of hydrogels present a challenge. This study aims to introduce a composite hydrogel that exhibits excellent mechanical, biological and printability properties simultaneously.Design/methodology/approachAlginate (Alg), carboxymethyl cellulose (CMC) and nanohydroxyapatite (nHA) as suitable materials for 3D printing were used. Effect of material content and pre-crosslinking on various properties of these materials were investigated. Both quantitative and qualitative experiments were conducted to validate the biomaterial ink’s printability, its rheological characteristics, as well as its biological and mechanical properties.FindingsBased on the analysis of the obtained experimental results from all mentioned tests, a hydrogel with a composition of 4% Alg, 2% CMC and 2% nHA with the pre-crosslinking process was selected as the preferred option. The results demonstrated that the selected material has good cell adhesion, wettability, degradation rate and 93% cell viability. Furthermore, compared to the composition of 4% Alg–2% CMC, the chosen material exhibited a 52% improvement in printability and a 55% improvement in compressive modulus.Originality/valueA significant challenge in the field of 3D bioprinting is the development of scaffolds that possesses optimal mechanical, biological and printability characteristics simultaneously, essential for attaining tissue-like properties. Hence, this paper explores a novel nanocomposite hydrogel that demonstrates promising outcomes across all these aspects simultaneously.

Natural bone is a complex material with a well-designed architecture. To achieve successful bone integration and regeneration, the constituents and structure of bone-repairing scaffolds need to be flexible and biocompatible. Hydroxyapatite (HAp), the main constituent of bone minerals, has excellent biocompatibility, while carboxymethyl cellulose (CMC), comprised of a three-dimensional network, has high flexibility. Therefore, CMC/HAp composites have attracted attention for the advancement of bone tissue engineering. In this work, a carboxymethyl cellulose/hydroxyapatite (Ca10(PO4)6(OH)2; HAp) composite has been developed as a three dimensional scaffold for bone tissue engineering. Scanning electron microscopy revealed that the CMC/Hap composite had a sheet like structure. These results revealed that the amount of precipitated HAp in the CMC/HAp composites was affected by the amount of CMC used during preparation. Properties of composites can be improved at optimal filler content compared to the pure Hap in the perspective of various biomedical applications. We have characterized the surface morphology of the composite using SEM image and having with the observed well dispersion of Hap in the Cmc phase.

Mechanical properties and micro-mechanism of improved shield tunnel muck with phosphogypsum and lime

In this study, the effect of polylactic acid (PLA) and carboxymethyl cellulose (CMC) coatings on the mechanical and physical properties of recycled packaging papers was investigated. Paper samples were produced according to the TAPPI T205-SP-02 standard using waste office paper and old corrugated cardboard. The physical and mechanical properties including Cobb values, burst index, tensile index, ring crush test (RCT), corrugated medium test (CMT), and corrugated crush test (CCT) were analyzed. Additionally, the chemical structure of the coated and uncoated papers was studied using Fourier-transform infrared spectroscopy (FTIR). CMC-coated papers exhibited significantly higher RCT, CMT, and CCT values compared to the uncoated samples. Furthermore, PLA hydrophobic characteristics significantly reduced water absorption, as reflected by lower Cobb values in coated samples. The combined PLA-CMC coating substantially enhanced both barrier and mechanical properties compared to uncoated samples. FTIR analysis confirmed chemical modifications in the cellulose matrix as a result of the coating process. These results confirmed that coating of the recycled packaging papers with combined CMC and PLA is a viable approach to improve their strength and water resistance, thereby supporting their potential use in sustainable packaging applications.