Mechanical and Thermal Properties of Nanoclay-Treated Banana Fibers

The objective of this work is to improve the thermal, mechanical and fiber-matrix adhesion properties of banana fibers using nanoclay particle infusion. The nanoclays were infused into the banana fibers by using alkaline and silane chemical treatments. The morphology and distribution of nanoclays in banana fiber was examined by scanning electron microscopy. Nanoclay infused fiber resulted in 35.7% and 12.5% increased tensile modulus and strength over untreated fiber, respectively. Thermogravimetric analysis of nanoclay infused banana fiber shows ~ 2.2 times increased weight gain at 600°C when compared with untreated banana fiber.     

Morphology,Structure, and Mechanical Properties of Natural Cellulose Fiber from Mendong Grass (Fimbristylis globulosa)

This study was to investigate the morphology, structure, and chemical properties of the Mendong fibers extracted from Mendong grass (Fimbristylis globulosa) in the form of raw and treated fiber by alkali-included chemical content and functional group and to evaluate the strength and properties of Mendong fibers compared with other natural fibers. These studies explore the chemical properties of the fiber including fiber composition and functional group by FTIR, mechanical properties of fiber, and the structural and morphological analysis of the fiber using SEM and XRD. The results showed that the chemical contents of Mendong fibers were 72.14% cellulose, 20.2% hemicellulose, 3.44% lignin, 4.2% extractive, and moisture of 4.2%–5.2%. Mechanical properties of the fiber were a strong character with tensile strength of 452 MPa, and modulus of 17 GPa. The structural properties of Mendong fiber such as crystallinity, crystalline index, microfibril angle, and crystalline size were 70.17% and 58.6%, 22.9°, and 14.3 nm, respectively. This fiber has competitive advantages compared with other natural fibers and can be developed further as a potential reinforcement of polymer matrix composites.     

Insitu Self-Assembly of Bacterial Cellulose on Banana Fibers Extracted from Peels

ABSTRACT

In this research work, in-situ self-assembly approach was used the first time, to cultivate bacterial cellulose on the surface of fibers, extracted from banana peels. The characterization was performed using SEM, FTIR, and single fiber tensile test in order to determine the surface morphology and mechanical properties of modified fibers. As-prepared hybrid fibers exhibited comparatively better mechanical properties, which can be attributed to the self-assembly of bacterial cellulose on banana fibers’ surface. Overall, this research work suggests a novel route for fiber extraction from banana peels and to use them for the preparation of bio nano-composites with improved mechanical properties.     

PSA和PPS耐高温纤维的结构与性能研究

通过红外光谱仪和X-射线衍射仪测定芳砜纶(PSA)纤维和聚苯硫醚(PPS)纤维的微观结构,用热分析仪测定两者的热分解温度,通过Instron电子强伸度仪测定两者受热前后的力学性能,并对两者结构与性能的差异进行比较。结果表明:PPS纤维的结构较PSA纤维稳定,结晶度高于PSA纤维;PSA纤维和PPS纤维的热分解温度分别为435.6℃和480℃,两种纤维均具有优异的耐热性能;PPS纤维的断裂强度和伸长均显著高于PSA纤维,两种纤维经高温处理后,强力损失均较小,经300℃处理200h后,强力仍保持90%左右。     

Microstructural Study,Tensile Properties,and Scanning Electron Microscopy Fractography Failure Analysis of Various Agricultural Residue Fibers

This paper presents an approach to examine the microstructural properties and mechanical behavior of coconut husks, banana pseudo-stem, pineapple leaf, and sugarcane bagasse fibers by scanning electron microscope and mini-tensile tester, respectively. Single fiber bundles were examined by using scanning electron microscope. Tensile tests were performed at different diameters (0.15–0.55 mm) and gauge lengths (10, 15, 20, and 30 mm/min) to assess the effects of diameter and gauge length on tensile properties. It was found that fibers consisted of different types of regularly arranged cells. The tensile strength (310 MPa) and Young’s modulus (7.4 GPa) of pineapple leaf fiber bundles showed the highest value compared to the other fibers. The tensile strength and Young’s modulus decreased with the increase of diameter and gauge length of fiber bundles. Scanning electron microscopic fractography analysis showed comparatively heterogeneous ruptures associated with more participants of microfibrils for pineapple leaf and banana pseudo-stem fibers compared to coconut husk and sugarcane bagasse fibers. These fractographic observations were discussed in the light of current knowledge of the microstructure of each fiber and the corresponding mechanical properties.     

拉伸残余应力对聚偏氟乙烯纤维力学性能的影响

为得到高断裂强度的聚偏氟乙烯(PVDF)纤维,在后处理过程中利用拉伸产生的残余应力对其进行定长处理实验。探究了该处理过程中最优的工艺条件参数,并利用热分析法、红外光谱法、X射线衍射法和应力拉伸实验等测试手段对纤维的晶体结构、晶区取向、晶粒尺寸、结晶度和力学性能进行测试与分析。结果表明：在残余应力作用的后处理过程中,PVDF发生了α晶型向β晶型的进一步转变,β晶型的含量从74.6%增加到88.7%;结晶度从49.4%增加到52.3%;晶区的取向程度提高,取向因子从0.793 2增加到0.833 4;纤维的断裂强度提升明显,特别在60 °C的水浴下处理3h 时,断裂强度可达到最大值633 MPa,相比未处理前提高了70 MPa。     

Borassus and Tamarind Fruit Fibers as Reinforcement in Cashew Nut Shell Liquid-Epoxy Composites

In this study borassus and tamarind fruit fibers were extracted and their physical and mechanical properties such as diameter, density, tensile strength and interfacial adhesion strength (IAS) were experimentally determined. To study the effect of alkali treatment, both the fruit fibers were treated with 5% vol. sodium hydroxide solution for 0.5 h, 1 h, 2 h, and 4 h durations. Morphological studies of untreated and alkali treated fibers by using scanning electron microscope (SEM) revealed the presence of the surface impurities on the untreated fiber whereas the same were absent on the treated fibers. Fourier transform infrared spectrometry (FTIR) and X-ray diffraction (XRD) analysis also confirmed the elimination of amorphous hemicellulose of the fibers on treatment. Borassus fruit fine fibers and tamarind fruit fibers treated for 2 h exhibited better mechanical properties and improved IAS with Cashew Nut Shell Liquid (CNSL) -Epoxy matrix.     

Effect of Green Gram Husk Nanocellulose on Banana Fiber Composite

Nanocellulose is a significant bio entity in the present-day applications of nanocomposites. In this regard, the present work focuses on fabrication of green gram husk cellulose-based hybrid nanocomposites. In the process of nanocellulose extraction, residues obtained after each stage of treatment are characterized through physical and morphological tests. Later, nanocellulose is reinforced in unsaturated polyester with 1, 3, 5, and 7 wt. % to study the tensile properties. The peak tensile strength is found to be 39 MPa at 5wt% of cellulose nanocomposites. Noting the enhancement in tensile properties of nanocomposites, nanocellulose is reinforced in banana fiber composites and its influence on mechanical properties is studied. Nanocellulose/banana fiber hybrid composites showed enhanced tensile strength, flexural strength, and impact strength.     

再生丝素纤维的湿法纺丝及其交联改性研究

以六氟异丙醇(HFIP)溶解再生丝素膜,通过湿法纺丝获得再生丝素纤维。再生丝素纤维经1-(3-二甲基氨基丙基)-3-乙基碳化二亚胺(EDC)和N-羟基丁二酰亚胺(NHS)作为交联剂进行后处理,利用扫描电镜(SEM)、红外光谱(FTIR)、X-射线衍射(XRD)、DSC热分析法、力学性能等表征方法研究和分析了牵伸和交联前后纤维聚集态结构和力学性能的变化。研究结果表明:再生丝素纤维经牵伸和EDC/NHS交联改性后,纤维直径变细为87μm,纤维内部结构以silk II结构为主;纤维的热稳定性提高,热分解峰峰值由281℃提高至288℃;纤维的断裂强度和断裂伸长率明显增大,分别达到1.41 cN/dtex和11.38%,表现出良好的柔韧性。     

Some Properties of Natural Fibers (Sisal,Pineapple, and Banana) in Comparison to Man-Made Technical Fibers (Aramide,Glass, Carbon)

In this paper, we analyze the results of the delignification treatments performed on three natural fibers (sisal, pineapple, and banana) and of the thermal treatments at 400, 600, and 800°C on three industrial fibers (aramid, carbon, and glass). The fibers were analyzed by TGA, SEM, and EDS, as well as tested for tensile strength before and after the delignification and thermal treatments. Contact angle measurements were also carried out on the natural fibers. With the delignification treatments, the removal of Si, K, and Mg on pineapple and banana fibers was achieved. Thermal treatments lowered significantly the tensile strength of industrial fibers, while delignification treatments decreased slightly the mechanical resistance of natural fibers, except in the case of the pineapple fiber.     

Polyvinyl Chloride Reinforced with Areca Sheath Fiber Composites—An Experimental Study

ABSTRACT

This research work deals with fibrous composites obtained by using treated and untreated areca sheath (AS) fibers reinforced in polyvinyl chloride (PVC) by injection molding process. Surface treatments of fibers have been carried out to have a better compatibility with PVC matrix. The tensile and flexural strength have been found to increase at the early stage with the increase in treated areca fiber content till optimum (18 wt% of fiber) fiber loading thereafter declines. At optimum fiber loading, the tensile strength, flexural strength and young’s modulus values are 42.38 MPa, 18.22 MPa and 2.38 GPa, respectively, which give maximum values in comparison to other fiber loadings. Thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), biodegradability tests and scanning electron microscopy (SEM) have been used for analysis. The TGA inferred that the thermal stability of the composites increased as compared to neat PVC matrix. Further, the composites exhibit excellent biodegradability property and their biodegradability increases with the increase of areca fiber content. From the properties obtained at optimum fiber loading (18 wt% of fiber), the composite can be suitable for automotive dashboard and door panel applications.     

Effect of Chemical Treatment on Thermal,Mechanical and Degradation Behavior of Banana Fiber Reinforced Polymer Composites

ABSTRACT

The current research endeavor, explores the thermal, mechanical, and degradation behavior of alkaline treated banana fibers reinforced polypropylene composites. Composites incorporating BF (20% w: w) treated with NaOH (5% w: v) aqueous solution were developed using extrusion-injection molding processes. After chemical treatment, the tensile, flexural and impact strength of the composite increases by 3.8%, 5.17%, and 11.50%, respectively. Scanning electron microscope (SEM) observations of tested specimens confirm the fiber pull out and fiber fracture as the main reasons for failure of developed composites under tensile and impact loading. The specimens were exposed to two different environments, water immersion and soil burial for 5 weeks for the degradation studies. The degradation behavior of composites was measured in terms of variation in weight and mechanical properties (tensile, flexural, and impact). The maximum degradation in mechanical properties was observed for the composites buried under soil. The composite lost 7.69%, 12.06%, and 3.27% of tensile, flexural, and impact strength, respectively.     

高性能聚酰亚胺纤维及其可织造性能

为推进高性能聚酰亚胺纤维在纺织材料领域的应用发展,分析了5 种商业化聚酰亚胺纤维的微观结构和力学性能,并通过全自动剑杆小样织机对其可织造性能进行了研究。借助红外光谱仪、X 射线衍射仪、扫描电子显微镜、纤维强伸度仪和纱线抱合力机对纤维的结构和性能进行表征。结果表明：5 种聚酰亚胺纤维中强度及模量最高纤维的亚胺化程度为97.26%,结晶度为19.27%,取向度为0.92,以上结构参数赋予其优异的力学性能,其强度和模量分别为2 239.24 MPa 和56.62 GPa,但伸长率较小,仅为4.03%;该纤维表面光滑、致密、具有明显的原纤结构,但耐磨性差,对其织造性能和织物表观形貌具有一定影响。     

高强度聚偏氟乙烯纤维的熔融纺丝法制备

为得到高拉伸强度的聚偏氟乙烯(PVDF)纤维,通过正交实验和单因素实验,研究了熔融纺丝法制备PVDF纤维的工艺条件,并利用热分析(DSC)、红外光谱法(FT-IR)、X射线衍射(XRD)和拉伸试验研究了纤维的晶体结构、晶区取向和力学性能。研究结果表明：纺丝过程中影响纤维拉伸强度的因素主次顺序为卷绕速率>喷头温度>喷嘴直径>入水距离,最优条件为卷绕速率10.2 m/min,喷头温度240 °C,喷嘴直径2.0 mm,入水距离40 cm;初生纤维既含有α晶型,也有β晶型,冷拉伸使得纤维发生α→β晶型转变,总体结晶度和取向度均有提高,拉伸强度明显提高,并在最大拉伸倍数6.5倍左右达到最大值591 MPa。     

乙烯-四氟乙烯共聚纤维的性能

为实现乙烯-四氟乙烯(ETFE)共聚纤维工业规模开发,通过熔融纺丝法制备了ETFE共聚初生纤维,并将初生纤维在150℃条件下通过电子拉伸试验机进行定长拉伸,得到拉伸比为100%和200%的纤维。利用热重分析仪、差示扫描量热分析仪、X射线衍射仪、动态热机械分析仪和电子拉伸机等分别测试了纤维的热性能、结晶结构、力学性能。测试得出:ETFE共聚热分解温度约为477℃;不同拉伸倍率纤维的熔融温度均保持在259℃左右;拉伸200%纤维断裂强度约为160 MPa,是初生纤维的3倍。结果表明:随拉伸倍率的提高,ETFE共聚纤维玻璃化转变温度提高9℃,结晶度和晶区取向度分别提高了10.2%和5.5%;经浓硫酸、氢氧化钠溶液、丙酮和次氯酸钠试剂处理后各纤维断裂强度均无明显变化,表现出良好的耐化学试剂性能。     

Effect of Thermal Aging and Chemical Treatment on Tensile Properties of Coir Fiber

Effect of thermal aging and chemical treatment on the physical properties of coir fiber was investigated. Coir fibers were treated with sodium hydroxide and glutaraldehyde for 2 h. The influence of alkali and aldehyde treatment on tensile strength and elongation at break was studied in detail. Enhancement in tensile strength of coir fiber was observed up to five days of aging at 50°C and further decreased. Thermal cross linking of cellulose present in the fiber may be the reason for the increase in tensile strength and thermal degradation due to the chain scission of cellulose reduced the tensile strength. Sodium-hydroxide-treated samples showed an increase in tensile strength and reduction in elongation at break. The removal of impurities such as waxy and fatty acid residues from the coir fiber by reacting with strong base solution improved the strength of fiber. Cross linking of cellulose with glutaraldehyde in the fiber reduced the elasticity and enhances the strength of the material. Scanning electron microscopy was employed to analyze the change in surface morphology upon chemical treatment. Improvement in the tensile strength suggests that NaOH and glutaraldehyde can be effectively used to modify coir fiber with excellent physical properties.     

Evaluation and Impact Factors of the Mechanical Properties of Phloem Bundle Fibers Obtained from Kenaf Germplasm

The mechanical properties of kenaf phloem bundle fibers are valuable for reinforced composites or boards, more so than similar materials also used in textile or papermaking applications. 55 kenaf germplasm studied here showed an average phloem bundle fiber tensile strength of 643.6 MPa and an average elastic modulus of 23.3 GPa after chemical retting treatment. 19 of these kenaf germplasm had fiber tensile strengths >700 MPa, which can be attributed to intensive breeding programs. The fiber tensile strength and elastic modulus of kenaf germplasm had a significant positive correlation, but there was no such correlation between a fiber’s mechanical properties and its diameter or agronomic characteristics. Among 56 hybridized combination F₁ generations, the highest tensile strength was 928.3 MPa from a combination of No.30 of Xinan Wuchi × Guatemala 4. Therefore, breeding and screening are both useful for improving the mechanical properties of kenaf phloem bundle fibers. However, the effects of the used bundle fiber preparation method or cultivation year on the fiber’s mechanical properties were more pronounced than those of the type of kenaf germplasm or breeding operation used. The mechanical properties of kenaf phloem bundle fibers treated by chemical retting were superior to those treated using natural retting.     

Airlaid nonwoven panels for use as structural thermal insulation

Thermal-bonded airlaid nonwoven webs consisting of fiber glass and polyester bicomponent fibers were manufactured, and then multilayer webs were formed into composite panels using compression molding technique. The consolidation process was optimized and the effect of bulk density on air permeabilites, mechanical properties, and thermal resistance was studied. Increasing binder amount and bulk density improved the flexural and tensile strength. Thermal resistance of the panels were found to be very dependent on the bulk density such that the resistance increased exponentially with an initial increase in density, then leveled off and decreased linearly with further increment in density. Depending on the composition and bulk density, the panels provided thermal resistance between 0.52 and 0.88 Km²/W, tensile strength between 2 and 7 MPa, and flexural strength between 600 and 3500 kPa. The findings revealed that airlaid nonwoven panels can be designed to use as structural thermal insulation materials in constructions.     

碱处理对涤纶/光敏树脂复合材料力学性能的影响

针对光敏树脂经3D打印成型后试样力学性能较差问题,采用涤纶长丝增强光敏树脂的方法,使用光固化3D打印设备将涤纶长丝和光敏树脂复合成型制备涤纶增强复合材料。为获得较好的增强效果,对涤纶进行碱处理,研究了碱处理各条件下涤纶的减量率与纤维形貌和力学性能的关系,以及其对复合材料力学性能的影响。结果表明:随着减量率的增加,涤纶的形貌及力学性能改变越明显;当涤纶减量率为16.2%时,纤维表面出现连续纵向沟壑,力学强度下降6%,纤维的增强效果最好;经过改性处理的涤纶增强复合材料的拉伸强度和弯曲强度分别达到78 MPa和471 MPa,相比于未处理的纤维增强复合材料分别提升了66%和336%。     

超临界CO2处理温度对二醋酸纤维结构与性能的影响

为拓展超临界CO₂技术在二醋酸纤维加工中的应用,采用不同超临界CO₂处理温度对二醋酸纤维进行处理,借助扫描电子显微镜、傅里叶变换红外光谱仪、X射线多晶衍射仪、热重分析仪、差示扫描量热仪和万能强力仪探讨了处理前后纤维表面形态、化学结构、聚集态结构、热降解性能、热稳定性和断裂强力的变化。结果表明:不同温度(80、100、120 ℃)条件下,纤维结晶度均有所下降,由处理前的39.41%分别降低至32.43%、31.57%、32.16%;当温度达120 ℃时,二醋酸纤维中部分氢键被破坏,纤维耐热性能、热稳定性有一定下降,但并不显著,纤维的表面形态、化学结构并未发生明显改变,拉伸断裂强力仍保持在3.20 cN左右。