Fiber Production Research Articles

A critical review on additive manufacturing of sustainable NFRCs: processing and applications

In present era researchers and scientists are rapidly acknowledging the importance of environment friendly procedures, goods, and the recycling of agricultural waste. Therefore, the utilization of natural resources and production of natural fiber reinforced composites (NFRC‘s), is increasing considerable interest among scientists. Although NFRC‘s have promising application potential, certain issues relating to materials and processes must be resolved to attain long-term stability and performance. The current study serves as a first introduction to the many categories and advantages of NFRC‘s and additive manufacturing, accompanied by a concise explanation. Furthermore, the present article provided a concise overview of characteristics and types of NFRC‘s, processing and recent challenges of implementing NFRC‘s in the field of additive manufacturing (AM). Finally, recent challenges encountered in processing NFRCs using additive manufacturing are briefly introduced. The Future scope of AM for sustainable NFRC‘s is very promising, especially in terms of enhancing environmental sustainability, improving efficiency, and enabling novel applications.

Machine learning-enhanced modeling and characterization for optimizing dietary Fiber production from Highland barley bran.

This study investigated the modification of highland barley bran through co-fermentation of Lactobacillus bulgaricus and Kluyveromyces marxianus, and developed a dynamic prediction model for DF content under these co-fermentation conditions using machine learning algorithms. The results showed that the XGBoost algorithm could predict changes in the DF component content (R2 = 0.9553(SDF/IDF), RMSE = 0.0464.) and identify optimal fermentation conditions. Under the optimal conditions, both strains exhibited synergistic effects, where the lactic acid produced by Lactobacillus bulgaricus and β-glucosidase produced by Kluyveromyces marxianus might facilitate IDF decomposition and conversion, resulting in a maximum SDF/IDF ratio of 0.6911. This led to a 27.65 % reduction in IDF content and a 19.11 % increase in SDF content. Moreover, the physicochemical and functional properties of DF were enhanced after co-fermentation. The structure of DF became more loose and porous, its thermal stability improved, and its water-holding, oil-holding, and swelling capacities increased by 53.54 %, 16.11 %, and 44.96 %, respectively, compared with the unfermented counterpart; In terms of adsorption characteristics, its glucose, cholesterol and nitrite adsorption capacities were also significantly improved. According to in vitro gastrointestinal simulated digestion, digestion would have a great impact on the fermented DF, which showed good antioxidant properties during the intestinal digestion stage.

Non-Circular Cross-Section Fibres for Composite Reinforcement—A Review with a Focus on Flat Glass Fibres

Glass fibre reinforcements form the backbone of the composites industry. Today, glass fibre products account for more than 95% of the fibre reinforcements used in the composites industry. Since the first commercialisation of glass fibres for composite reinforcement in the 1930s, the cross-sectional shape of glass fibres has remained exclusively circular. However, many of the other types of fibre reinforcement have a non-circular cross section (NCCS). This paper reviews the available knowledge on the production of NCCS glass fibres and some of the possibilities that such fibres offer to enhance the performance of glass reinforced polymer composites. The three parts of the review focus on early research work on different shapes of glass fibre, the developments leading to industrial-level production of NCCS glass fibres, and the more recent data available on the influence of the available commercially produced NCCS flat glass fibres on composite performance. It Is concluded that the continued development of NCCS glass fibres may offer interesting potential to generate composites with increased performance and may also enable further tailoring of composite performance to enable new applications to be developed.

Effects of Moisture Content and Heat Treatment on the Viscoelasticity and Gelation of Polyacrylonitrile/Dimethylsulfoxide Solutions

Polyacrylonitrile (PAN) gels create significant obstacles in industrial fiber spinning by forming insoluble networks that compromise solution stability and uniformity. This study investigates the rheological properties of PAN/dimethyl sulfoxide (DMSO) solutions, examining how aging time, moisture content, and polymer concentration affect gelation behavior. Dynamic rheological analysis revealed that both physical and chemical crosslinks play crucial roles in gel formation, with gelation accelerating markedly when moisture content exceeds 3% and aging progresses. Under heat treatment at 80 °C, samples with increased moisture content demonstrated rapid transitions to solid-like states, indicating a critical moisture threshold for enhanced gelation kinetics. Additionally, reductions in polymer concentration disrupted physical crosslink density, thereby mitigating gel formation. These results underscore the importance of precisely controlling moisture and concentration parameters in PAN solutions to stabilize solution properties and minimize gel formation, thus enhancing process efficiency and quality in PAN-based carbon fiber production.

Preparation of hemp‐based biocomposites and their potential industrial application

AbstractBiocomposites are an emerging field in plastic industry. The incorporation of agri‐food waste in conventional or biobased polymer matrices allows the industry to lessen its carbon footprint, while producing recyclable plastic products. In this work, hemp hurd, a byproduct of hemp fiber production process, was used as a filler to prepare novel compostable composites in two different loadings (22% and 32% w/w respectively). Waste hemp hurds were selected due to their abundance and the lack of derived high‐value products. Three different polymers were used, namely poly[(tetramethyleneadipate)‐co‐(tetramethyleneterephthalate)] (PBAT) and poly(tetramethylene succinate) (PBS) as compostable polymers and a polyethylene elastomer for comparison. The bare polymers and prepared blends were then characterized for their structure and morphology by XRD and FESEM, as well as for their wettability, thermal and mechanical properties (namely energy absorbed on impact and flexural modulus). Structural and morphological characterization unveiled the different interactions occurring between hemp and the polymer matrices, suggesting the major impact of the type of used polymer when compared with biomass loading percentages. Mechanical tests showed that both PBAT and PBS blends properties are comparable to those of the pure polymers (i.e., in the case of PBAT the flexural modulus of the pure polymer was 82.2 MPa while the hemp‐loaded blends stood at around 50 MPa, whereas all PBS polymers and blends were 220 MPa, with no statistical difference between samples). These biomaterials have also similar thermal properties with respect to the bare polymers, underlining the promising potential as sustainable alternative to pure polymers.Highlights Waste hemp hurds were used to load biodegradable polymers at different percentages. Hemp hurd‐based biomaterials with excellent properties were prepared. Polymer flexural behavior was maintained even after hemp addition. Polymer‐hemp interactions for each polymeric matrix were elucidated. Hemp substitutes up to 32% w/w of polymer without affecting its properties.

Microfocused Ultrasound in Regenerative Aesthetics: A Narrative Review on Mechanisms of Action and Clinical Outcomes.

Microfocused ultrasound with visualization (MFU-V) is widely used in aesthetic medicine for skin tightening and rejuvenation. However, its role in regenerative aesthetics and its precise mechanism of action are not fully understood. This narrative review aims to contextualize and articulate the mechanism of action of MFU-V, evaluate its role in regenerative aesthetics, and assess its effectiveness based on existing clinical, histological, and skin-mechanical studies. A comprehensive literature search was performed to collect and analyze studies on MFU's biological mechanisms, clinical outcomes, and impact on extracellular matrix (ECM) regeneration. The review integrates findings from clinical trials, histological analyses, and biomechanical assessments to provide a cohesive understanding of MFU-V's role in aesthetic medicine. MFU-V emits focused ultrasound energy that penetrates multiple skin layers and the superficial musculoaponeurotic system, creating localized thermal coagulation points. These points initiate biological responses that recruit fibroblasts and stimulate the production of new collagen and elastin fibers. Enhanced ECM protein synthesis leads to significant improvements in skin biomechanics and quality, reducing skin laxity and enhancing appearance. Clinical studies support these findings, showing improvements in skin firmness and texture following MFU-V treatment. Through analyzing the underlying biological mechanisms and the observable clinical outcomes, this narrative review sets the stage for a comprehensive understanding of the mechanism of action and role of MFU-V in regenerative aesthetics.

Drug-Eluting and Antibacterial Core-Shell Polycaprolactone/Pectin Nanofibers Containing Ti3C2Tx MXene and Medical Herbs for Wound Dressings.

Fibrous scaffolds capable of delivering natural drugs and herbs show great promise for tissue regeneration and wound care, particularly in personalized medicine. This study presents the fabrication and characterization of drug-eluting antibacterial core-shell mats composed of polycaprolactone (PCL) and pectin nanofibers produced through coaxial electrospinning. Berberine chloride (BBR), an herbal compound with antineoplastic, anti-inflammatory, antilipidemic, and antidiabetic properties, served as the model drug. Poly(vinyl alcohol) (PVA) was blended with pectin to enhance the mechanical properties of the core fibers. The shell was modified with two-dimensional Ti3C2Tx (MXene) nanosheets and subjected to covalent and ionic cross-linking. Structural analysis confirmed the successful production of bead-free fibers with diameters ranging from 160 to 350 nm, depending on composition. The PCL core fibers were uniformly coated with a pectin/PVA shell approximately 90 nm thick. The inclusion of BBR and MXene increased the fiber diameter. Drug-release kinetics, modeled by using Korsmeyer-Peppas, revealed a two-stage release mechanism. An initial burst release occurred within the first 24 h (kinetic exponent n = 1.36), followed by sustained release over 2 weeks (n = 0.48). The release mechanisms were identified as case-II relaxational release in the first stage, transitioning to quasi-Fickian diffusion in the second. Incorporating MXene into the shell further prolonged drug release. The mechanical strength of the scaffolds improved significantly by a factor of 7 and 4 in wet and dry conditions, respectively. In vitro biocompatibility assays using L929 cells demonstrated excellent cell attachment and compatibility. Additionally, antibacterial tests against Escherichia coli showed that the inclusion of MXene enhanced antibacterial activity by 30%. These results suggest that the functional biocomposite scaffolds hold the potential for developing innovative, drug-eluting wound dressings.

Microbial communities and their role in enhancing hemp fiber quality through field retting.

The current development of industrial hemp "Cannabis Sativa L." fibers for technical textiles and industrial applications requires high-quality fibers with homogeneous properties. However, several factors have been reported to influence the fibers' intrinsic properties, including a post-harvest process known as retting. This process plays a crucial role in facilitating the mechanical extraction of fibers from hemp stems. Retting involves the degradation of the amorphous components surrounding the fiber bundles enabling their decohesion from stems. Microorganisms play a central role in mediating this bioprocess. During retting, they colonize the stems' surface. Therefore, the biochemical components of plant cell wall, acting as natural binding between fibers, undergo a breakdown through the production of microbial enzymes. Although its critical role, farmers often rely on empirical retting practices, and considering various biotic and abiotic factors, resulting in fibers with heterogenous properties. These factors limit the industrial applications of hemp fibers due to their inconsistent properties. Thus, the purpose of this review is to enhance our comprehension of how retting influences the dynamics of microbial communities and, consequently, the evolution of the biochemical properties of hemp stems throughout this process. Better understanding of retting is crucial for effective process management, leading to high-value fibers. KEY POINTS: • Retting enables degradation of cell wall components, controlling fiber properties. • Microbial enzymatic activity is crucial for successful decohesion of fiber bundles. • Understanding retting mechanisms is essential for consistent fiber production.

Evaluating priority strategies for decarbonising offshore wind turbine blades through lifecycle assessment

Abstract While offshore wind is at the early stage of expansion, global capacity is expected to increase rapidly, reaching 330 GW by 2031. This work uses lifecycle assessment (LCA) to evaluate the opportunity for offshore wind energy decarbonisation through wind blade sustainable developments. The findings from the LCA are used to give informed recommendations towards priority areas of development across the blade lifecycle, that are critical to accelerate the sector’s transition towards net-zero targets. The production of raw materials was found to be the largest contributor to cradle-to-gave global warming potential (GWP). The sector should prioritise the utilisation of more sustainable materials, with an emphasis on the decarbonisation of carbon fibre production. Waste produced during blade manufacturing alone accounts for 10% of the blade’s GWP; therefore, increasing the material efficiency in this phase of the lifecycle is a significant opportunity for blade decarbonisation and should be a focus for the sector going forward. O&M was found to be the second largest contributor to GWP, with full decarbonisation of O&M practices potentially realising an 8% reduction in GWP. A range of alterative blade material scenarios were analysed, finding that recyclable resin systems have the greatest potential to decarbonise offshore blades. There are currently no commercial recycling operations for these resins therefore scale up of the recycling technologies is needed before they can be recycled in practice. Additionally, the development of low impact, economically viable circular solutions for legacy blade waste must be an immediate priority for the wind energy sector, given the anticipated exponential growth in global wind turbine blade waste generation. Graphical abstract

Opportunities for carbon sequestration from removing or intensifying pasture-based beef production

Pastures, on which ruminant livestock graze, occupy one third of the earth's surface. Removing livestock from pastures can support climate change mitigation through carbon sequestration in regrowing vegetation and recovering soils, particularly in potentially forested areas. However, this would also decrease food and fiber production, generating a tradeoff with pasture productivity and the ruminant meat production pastures support. We evaluate the magnitude and distribution of this tradeoff globally, called the "carbon opportunity intensity" of pastures, at a 5-arcminute resolution. We find that removing beef-producing cattle from high-carbon intensity pastures could sequester 34 (22 to 43) GtC i.e. 125 (80 to 158) GtCO2 into ecosystems, which is an amount greater than global fossil CO2 emissions from 2021-2023. This would lead to only a minor loss of 13 (9 to 18)% of the global total beef production on pastures, predominantly within high- and upper-middle-income countries. If areas with low-carbon intensity pastures and less efficient beef production simultaneously intensified their beef production to 47% of OECD levels, this could fully counterbalance the global loss of beef production. The carbon opportunity intensity can inform policy approaches to restore ecosystems while minimizing food losses. Future work should aim to provide higher-resolution estimates for use at local and farm scales, and to incorporate a wider set of environmental indicators of outcomes beyond carbon.

A Novel method of controlling the molecular weight of PAN-Lignin copolymer - synthesis and characterization

Polyacrylonitrile-lignin copolymer (PLC) has been successfully prepared via solution polymerization technique by a three step synthesis procedure. The main aim of this research is to control the molecular weight of the PLC by varying the initiator, monomer or solvent concentration in the reaction. The loading of lignin was kept constant which is 20 wt % in the PLC. The Polyacrylonitrile (PAN) homopolymer synthesized in the first step and the final copolymer PLC were characterized by various techniques such as FTIR, NMR, DSC, UV etc. The chemical bonding of lignin with the PAN backbone has been ascertained by these characterisation methods. This study explores a promising way to control the molecular weight of PLC copolymer which can be further used in the production of precursor fibre for carbon fibre.

A polymer blend containing polycarbosilane and polysilaethylene for designing improved silicon carbide based fibers

This study elucidates the characterization of silicon carbide fibers synthesized from a polymer blend comprising polycarbosilane (PCS) and polysilaethylene (PSE). Given that PSE lacks oxygen in its molecular structure and possesses a C/Si ratio of 1, akin to polymethylsilane (PMS)—which historically has been combined with polycarbosilane to enhance ceramic yields—it was anticipated that PSE would similarly augment the ceramic yield of the fibers post-pyrolysis. Unlike PMS, PSE exhibits compatibility with PCS up to 15 wt%, with a notable reduction in melt spinnable temperature when the PSE content surpasses 5 wt%. Fibers containing 5 wt% PSE, melt-spun at 603 K, developed a central hollow in the cross-section, attributed to hydrogen gas evolution from PSE. Incorporating 10 wt% or more PSE improved spinnability and facilitated the production of fibers with finer diameters. Ceramic yield after pyrolysis at 1273 K for 1 h was improved compared to fibers without PSE or with PMS, and after holding at 573 K for 2 h, the yield increased when subjected to an additional hold at 573 K for 2 hours, due to an increase of cross-linking in the samples.

Congo red Removal using Microwave assisted Pyrolysis derived Magnetic Hemp hurd Biochar

Industrial hemp hurd (HH) are the residue obtained after the decortication of the hemp plant for fibre production, which is seldom explored for biochar potential and as adsorbent for dye removal. The present study focused on the microwave-assisted pyrolysis (MAP) of HH for biochar production, magnetization and application for Congo red (CR) removal from aqueous solutions. Magnetic hemp hurd biochar (MHB) depicted a heterogeneous surface with 4.84µm pore size, 17.64 m2/g surface area, and 10.05wt. % Fe. CR removal of 92% was achieved under optimum conditions i.e., treatment time: 120min, pH: 8, and initial CR concentration: 10mg/L with MHB dosage of 0.6g/L. The CR adsorption on MHB was well-fitted with the Freundlich isotherm (R2 - 0.971), owing to the heterogeneous surface of MHB. A strong match with pseudo-second order model (R2 - 0.973), indicated chemisorption as the likely adsorption mechanism. MHB exhibited 87% CR removal efficiency after three successive reutilization cycles. The outcomes of CR removal efficiency and MHB reusability indicated its potential application for adsorptive removal of CR from aqueous systems.

Isolation of Cellulose Nanofibers From Sunflower Seed Husks via Formic Acid Hydrolysis

ABSTRACTNanocellulose has garnered great interest among researchers because of its biodegradability, renewability, biocompatibility, high strength and versatile functionality. The present study focuses on the development of an eco‐friendly, benign method to extract cellulose nanofibrils (CNFs) from waste sunflower husks (SFHs) using formic acid hydrolysis. Both CNFs and microcrystalline cellulose (MCC) were obtained in high yields from SFHs. The enhanced colloidal stability of CNFs was evident from the ζ potential values, which ranged from −11.8 to −19.6 mV. Varying yields of CNFs were obtained by differing reaction times, though all were found to be thermally stable. SEM and TEM were used for the morphological analysis. The removal of non‐cellulose constituents was confirmed by FTIR spectroscopy. The enhancement of crystallinity upon treatment was examined using XRD analysis. The thermal stability of the cellulose extracted was checked via TGA. The present method of extraction of CNFs and MCC from waste SFHs using formic acid could open a new way of bulk production of nanocellulose fibers for the manufacture of green, value‐added products in high‐end fields, including electronics, agriculture and biomedicine, among others.

Histopathological Correlation Between High Endothelial Venule Neogenesis and the Tumor Microenvironment in Lung Adenocarcinoma.

The dynamic interplay between cancer cells and the microenvironment involves a wide range of intricate relationships that evolve during different stages of tumor progression. Recent attention has focused on high endothelial venules (HEVs), specialized endothelial cells in tumors with a unique cuboidal shape similar to those in lymph nodes. Previous animal studies have shown that normalization of tumor angiogenesis through anti-VEGFR2 therapy promotes HEV formation. However, few reports exist regarding the relationship between HEVs and preexisting blood vessels or interstitial fibers. In this study, we histologically examined whether tumor vascular structure correlates with HEV neogenesis. A total of 109 patients with pathological stage I lung adenocarcinoma who had undergone curative lung resection at our Institute between 2012 and 2016 were included. HEVs were identified by anti-peripheral node addressin (PNAd) staining. Immunostaining and Elastica-Masson-Goldner staining were performed on tumor sections and quantified. PNAd-positive cells were identified in 102 (93.6%) patients. Nearly all PNAd-positive cells were located within or near immune cell clusters. We investigated the correlation between microvessel structures or interstitial fibers and the number/density of PNAd-positive vessels, but no significant correlation was found. Since PNAd-positive cells were concentrated in immune cell aggregates, we focused our analysis specifically on these regions. Immune cell aggregates with abundant PNAd-positive vessels had a greater microvessel density along with by rich collagen fiber production, and displayed a more mature morphological phenotype of HEVs. The generation of PNAd-positive cells in tumors is governed by an angiogenetic mechanism distinct from that of broader tumor microenvironment. Furthermore, the accumulation of immune cells is associated with increased HEV maturation.

PRODUCTION AND EXPORT PERFORMANCE OF COIR PRODUCTS IN INDIA

The coir sector is an important agro-based industry in India that plays an important role in employment opportunities and economic development. India is the world's largest producer and exporter of coir and coir products, exporting coir and its products to more than a hundred countries. It is the by-product of coconut's outer shell, which is used to produce coir fiber, coir yarn, different mats, mating rugs, non-woven products, non-woven mats, coir geo-textiles, coir pith, garden articles, curled coir, needle felt, hand knotted netting, coir ply articles, coir braid, coir rope, coir tea leaf bags, coir brushes, lunch bags, office bags, chapels, pouches, and many more. It is a 100 percent natural and biodegradable product that helps to store water molecules in soil to improve its fertility. The aim of the study is to determine the trend in production of coir fiber and its products in India and to know the export performance of coir fiber and its products in India during the last ten years. According to the study release, there are good opportunities in the world market for the coir products. KEY WORDS: coir fiber, coir products, production, exports, value, countries etc.

Genetics of Some Wool Traits in Sheep: A Review

Greasy fleece yield, staple length and fibre diameter are complex quantitative traits influenced by various genetic and environmental factors. Among non-genetic factors year of birth, gender of lamb, centre of rearing, parity and type of birth are known to influence wool traits in different sheep genetic resources. To develop effective breeding objectives and accurately evaluate genetic potential, more precise analysis of genetic parameters and correlations between growth traits is essential. However, inconsistent results were observed across breeds and studies, highlighting the need for breed-specific optimization strategies. Greasy fleece yield, fibre diameter and staple length are critical determinants of wool quality and quantity. Wool traits are moderately (20–50%) to highly heritable (≥50%), so improving quality and quantity of a wool clip can happen even after one generation. The significant variations observed among breeds underscore the need for breed-specific optimization strategies. By integrating genetic and environmental factors, sheep breeders and producers can develop effective breeding programs, improve wool production, and enhance profitability. Wool traits are moderately to highly heritable, however, very low and very high estimates have also been reported in different sheep genetic resources. The heritability estimates correspond to the genetic variation in a trait. Gene mapping has identified chromosomal regions influencing fibre quality and production, enabling more efficient selection of superior wool production. Recent studies have employed various techniques to investigate the impact of fibre-related genes, including the candidate gene approach, transcriptome analysis and genome-wide association studies. It is concluded that wool traits being quantitative in nature are governed by different genes and are influenced by genetic and different environmental factors.

Mechanisms of Cannabis Growth Promotion by Bacillus velezensis S141.

Cannabis sativa L. has a variety of uses, including fiber production, food, oil, and medicine. In response to environmental concerns regarding chemical fertilizers, Bacillus velezensis S141 was examined as a plant-growth-promoting bacterium (PGPB) for cannabis. This study evaluated the effects of S141 on cannabis growth and utilized transcriptomic analysis to identify the responsive pathways. Inoculation with S141 significantly increased growth in laboratory and field environments, with most of the bacteria residing in the leaves, followed by the stems and roots, as determined by quantitative polymerase chain reaction (qPCR). Transcriptomic analysis revealed 976 differentially expressed genes. Upregulated genes were associated with metabolism, cellular processes, and catalytic activities, especially in the biosynthesis of phenylpropanoid, plant-pathogen interactions, and hormone signaling pathways. S141 mutants deficient in the production of auxin and cytokinin displayed reduced growth enhancement, which affirmed the roles of these hormones in cannabis development. These findings emphasize the potential of S141 as a sustainable growth promoter for cannabis and provide insights into the underlying pathways it influences.

Penggunaan Slurry sebagai Pupuk Organik terhadap Kualitas dan Fermentabilitas Rumput Setaria (Setaria splendida Stapf) di Rumen

Biogas slurry is an organic product derived from livestock manure and produced through an aerobic fermentation process that can be used to improve soil fertility, forage production, and quality. This study aimed to investigate the effect of slurry organic fertilizer on crude protein content, crude fiber, and total fermentation gas production in the rumen in vitro . The study was conducted in a completely randomized design (CRD), consisting of five treatments of slurry levels as organic fertilizer and four replications consisting of two experimental units. The treatments consisted of S0 = without slurry, S1 = slurry 20 g/polybag, S2 = slurry 25 g/polybag, S3 = slurry 30 g/polybag, and S4 = slurry 35 g/polybag. The variables measured in this study were crude protein content, crude fiber, and total fermentation gas production. The data obtained were analyzed using a variance analysis (ANOVA). Duncan’s test was used to determine the effect of different levels of slurry on the measured parameters. The results showed that the use of slurry as an organic fertiliser increases crude protein content by an average of 16.06%, increases crude protein production from 1.47 g/poly bag to 96.38 g/poly bag and improves fermentability in the rumen by an average of 8.08% of setaria grass (Setaria splendida Stapf). The use of slurry at the level of 35 g/poly bag is recommended for the cultivation of setaria grass (Setaria splendida Stapf).

Evaluating storage conditions on the effect of peroxide content in acrylonitrile

AbstractThe content of peroxide in acrylonitrile is critical for the production of polyacrylonitrile‐based carbon fibers. Peroxide‐free acrylonitrile is used as a blank solution for testing the peroxide content of acrylonitrile, which storage conditions are important to the test. Of course, for the change of peroxide content in acrylonitrile stored for a period of time has an effect on the production of carbon fiber. In order to study the effect of storage conditions on peroxide in peroxide‐free acrylonitrile and acrylonitrile, the changes at refrigerator and room temperature were studied, respectively. Studies have shown that storage at temperatures below 20 °C for 3 months hardly affect the use of either peroxide‐free acrylonitrile or acrylonitrile. The experimental results obtained are useful for practical production and testing, which can improve the accuracy of testing and stability of production.