Structure and Properties of Natural Cellulose Extracted from Pineapple Leaf

2013 ◽  
Vol 815 ◽  
pp. 379-385 ◽  
Author(s):  
Tiao Kun Fu ◽  
Ji Hua Li ◽  
Qing Huang Wang ◽  
He Huang ◽  
Xiao Yi Wei ◽  
...  
Keyword(s):  
Amorphous Region ◽  
Regenerated Cellulose ◽  
Crystalline Region ◽  
Ftir Analysis ◽  
Structure And Properties ◽  
Cellulose I ◽  
Porous Network ◽  
Agriculture Waste ◽  
Natural Cellulose ◽  
Pretreatment Conditions

Utilization of agriculture waste has been an issue around the world. In this study, the natural cellulose was extracted from pineapple leaf. Under the optimal pretreatment conditions of 25 g/L, 368 K and 6 h, the ratio of obtained cellulose was above 85 wt%. The structure of obtained cellulose at different stage was confirmed by XRD results. Origin cellulose (OC) and pretreated cellulose (PC) belong to be cellulose I, while regenerated cellulose possessed cellulose II structure, attributed to the dissolution of ionic liquid which destroyed the hydrogen bonds between the cellulose molecules. On the other hand, the structure could be explained by the morphology analysis of OC, PC and RC. The porous network structure of RC led to the reduction of ordered crystalline region and the decrease of crystallinity (CrI), which was proved by BET results. However, the dissolution was testified to be a physical process through FTIR analysis, the existence of characteristic absorption peaks of cellulose. The thermal stability was decreased through pretreatment, dissolution processes, corresponding to the decrease of CrI. The disordered amorphous region of RC decides convenient for production and broad applications.

Preparation and Properties of Regenerated Sisal Cellulose from a Homogeneous Solution

2014 ◽  
Vol 700 ◽  
pp. 265-269
Author(s):  
Fei Wang ◽  
Huan Liu ◽  
Ji Hua Li ◽  
Xiao Yi Wei ◽  
Yi Hong Wang ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Homogeneous Solution ◽  
Regenerated Cellulose ◽  
Cellulose Ii ◽  
Optimal Conditions ◽  
Cellulose I ◽  
Natural Cellulose ◽  
Ft Ir ◽  
Ir Analysis ◽  
Application Fields

The sisal cellulose was dissolved in ILs under optimal conditions of 150°C and 400W. The structure of sisal cellulose was changed from cellulose I to cellulose II, accompanied with the decrease of crystallinity through XRD, FT-IR analysis. According to the result of GPC, molecular weight distribution became more uniformly and narrow. This is because intra-and inter-hydrogen bond existed in cellulose were destroyed during the dissolution process in ILs. And the regenerated cellulose possessed better properties than the former, which could broaden the application fields of natural cellulose.

scholarly journals Structure and Properties of Regenerated Cellulose Film with Fluorocarbon Coating

2012 ◽  
Vol 32 ◽  
pp. 706-713 ◽  
Author(s):  
Yuhui Zhang ◽  
Quan Ji ◽  
Hongjin Qi ◽  
Zengji Liu
Keyword(s):  
Regenerated Cellulose ◽  
Structure And Properties ◽  
Cellulose Film ◽  
Regenerated Cellulose Film

Diffusivity of solvents in semi-crystalline polyethylene using the Vrentas-Duda free-volume theory

2018 ◽  
Vol 38 (10) ◽  
pp. 925-931 ◽  
Author(s):  
Derek R. Sturm ◽  
Kevin J. Caputo ◽  
Siyang Liu ◽  
Ronald P. Danner
Keyword(s):  
Free Volume ◽  
Weight Fraction ◽  
Amorphous Region ◽  
Model Parameters ◽  
Crystalline Region ◽  
Free Volume Theory ◽  
Melt Temperature ◽  
Tortuosity Factor ◽  
Crystalline Polyethylene

Abstract Diffusion of penetrants in polyethylene below the melt temperature is heavily dependent on the crystallinity of the polyethylene, the temperature of the experiment, and the concentration of solvent in the polymer. As the crystallinity of the polyethylene increases, there is an increase in the path that the solvent must travel as the solvent cannot penetrate the tightly packed chains in the crystalline domain. This effect is typically accounted for by a tortuosity factor. In this work, a simple and effective characterization of the tortuosity factor based simply on the crystal weight fraction has been developed. Data have been collected for six polyethylenes having densities ranging from 0.912 to 0.961 g/cm3 and for three solvents – isopentane, cyclohexane, and 1-hexene. Diffusivity predictions have been obtained using the free-volume theory of Vrentas and Duda in conjunction with the new tortuosity factor. The polyethylenes had crystallinities varying from 40% to 82% effecting an approximately 60% change in the diffusivity. The decrease resulting from ignoring the crystallinity altogether was in some cases essentially a factor of 5. The error in the predicted diffusivities over all the systems was 25%. For cyclohexane, it is shown that the same model parameters characterize data below the melt temperature (in the semi-crystalline region) as well as above the melt temperature (in the amorphous region).

Morphological, structural and physicochemical properties of rice starch nanoparticles prepared via ultra-high pressure homogenization

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Chengyi Sun ◽  
Yuqing Hu ◽  
Xietian Yu ◽  
Zhijie Zhu ◽  
Shuai Hao ◽  
...  
Keyword(s):  
High Pressure ◽  
Physicochemical Properties ◽  
Particle Diameter ◽  
Amorphous Region ◽  
Rice Starch ◽  
Crystalline Region ◽  
High Pressure Homogenization ◽  
Relative Crystallinity ◽  
Ultra High Pressure ◽  
Starch Nanoparticles

Abstract Native rice starches were treated with five periods of ultra-high pressure homogenization (UHPH) under each of 60, 80, 100, 120, 140 and 160 MPa, respectively. The morphological, structural and physicochemical properties of starches treated with UHPH were examined. The mean particle diameter of starch nanoparticles ranged between 154.20 and 260.40 nm. SEM revealed that the granular amorphous region of starch granules was damaged under pressures between 60 and 80 MPa, and the crystalline region was further destroyed under pressures as high as 100–160 MPa. DSC demonstrated that the gelatinization temperatures and enthalpies of nanoparticles reduced. The relative crystallinity reduced from 22.90 to 13.61% as the pressure increased. FTIR showed that the absorbance ratio at 1047/1022 cm−1 decreased, and increased at 1022/995 cm−1. RVA results indicated that the viscosity of starch samples increased between 60 and 120 MPa, and the reverse effect was observed under 140 and 160 MPa.

Study on effect of supercritical CO2 on structural ordering and charge transporting property in thiophene-based block copolymer

2022 ◽  
Author(s):  
Satomi Hosokawa ◽  
Eri Tomita ◽  
Shinji Kanehashi ◽  
Kenji Ogino
Keyword(s):  
Supercritical Co2 ◽  
Hole Mobility ◽  
Amorphous Region ◽  
Crystalline Region ◽  
Space Charge Limited Current ◽  
Conjugation Length ◽  
Enhanced Mobility ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene ◽  
Effective Conjugation Length

Abstract We reported that supercritical (sc) annealing of poly(3-hexylthiophene) (P3HT), and its block copolymers with poly(ethylene oxide) (PEO) and polystyrene (PSt) brought about improvements in the crystal structure and hole mobility, determined by the space charge limited current (SCLC) measurement. P3HT-b-PEO showed the largest increase in mobility. From XRD profile, it was found that the treatment with scCO2 increased the crystallite size and crystallinity. UV-vis spectra showed that the effective conjugation length in the scCO2 treated films was increased compared to the as-spun, suggesting that CO2 molecules are incorporated into domains of the second block domains and P3HT amorphous region, and assist to alter the characteristics of the crystalline region. Then, it was considered that the change in the crystalline structure and the improvement of P3HT chains packing led to the enhanced mobility. Since PEO is known to have a higher affinity for CO2, the increase of mobility was specifically intensive.

scholarly journals Reclaimed Rubber/Poly(ε-caprolactone) Blends: Structure, Mechanical, and Thermal Properties

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1204 ◽  
Author(s):  
Aleksander Hejna ◽  
Łukasz Zedler ◽  
Marta Przybysz-Romatowska ◽  
Javier Cañavate ◽  
Xavier Colom ◽  
...  
Keyword(s):  
Global Scale ◽  
Waste Materials ◽  
Mechanical And Thermal Properties ◽  
Ftir Analysis ◽  
Structure And Properties ◽  
Scanning Calorimetry ◽  
Good Thermal Stability ◽  
Waste Rubber ◽  
Interfacial Compatibility ◽  
Dynamic Mechanical Testing

The amount of elastomeric waste, especially from tires is constantly increasing on a global scale. The recycling of these residua should be considered a priority. Compounding the waste rubbers with other polymers can be an excellent alternative to reuse waste materials. This procedure requires solving the issue of the lack of compatibility between the waste rubber particles and other polymers. Simultaneously, there is a claim for introducing biodegradable plastics materials to reduce their environmental impact. In this work, reclaimed rubber/poly(ε-caprolactone) (RR/PCL) blends are proposed to enhance the recycling and upcycling possibilities of waste rubbers. The results show that the addition of PCL to the RR allows obtaining blends with improved mechanical properties, good thermal stability, and enhanced interfacial compatibility between the used components. Structure and properties of the proposed RR/PCL have been studied by means of static and dynamic mechanical testing, Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA)-FTIR analysis.

scholarly journals Thermo-Mechanical Behaviour of Human Nasal Cartilage

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 177 ◽  
Author(s):  
Aureliano Fertuzinhos ◽  
Marta A. Teixeira ◽  
Miguel Goncalves Ferreira ◽  
Rui Fernandes ◽  
Rossana Correia ◽  
...  
Keyword(s):  
Mechanical Behaviour ◽  
Subcutaneous Tissue ◽  
Amorphous Region ◽  
Cartilage Matrix ◽  
Water Evaporation ◽  
Glass Transition Point ◽  
Crystalline Region ◽  
Scanning Calorimetry ◽  
Nasal Cartilage ◽  
Human Nose

The aim of this study was to undergo a comprehensive analysis of the thermo-mechanical properties of nasal cartilages for the future design of a composite polymeric material to be used in human nose reconstruction surgery. A thermal and dynamic mechanical analysis (DMA) in tension and compression modes within the ranges 1 to 20 Hz and 30 °C to 250 °C was performed on human nasal cartilage. Differential scanning calorimetry (DSC), as well as characterization of the nasal septum (NS), upper lateral cartilages (ULC), and lower lateral cartilages (LLC) reveals the different nature of the binding water inside the studied specimens. Three peaks at 60–80 °C, 100–130 °C, and 200 °C were attributed to melting of the crystalline region of collagen matrix, water evaporation, and the strongly bound non-interstitial water in the cartilage and composite specimens, respectively. Thermogravimetric analysis (TGA) showed that the degradation of cartilage, composite, and subcutaneous tissue of the NS, ULC, and LLC take place in three thermal events (~37 °C, ~189 °C, and ~290 °C) showing that cartilage releases more water and more rapidly than the subcutaneous tissue. The water content of nasal cartilage was estimated to be 42 wt %. The results of the DMA analyses demonstrated that tensile mode is ruled by flow-independent behaviour produced by the time-dependent deformability of the solid cartilage matrix that is strongly frequency-dependent, showing an unstable crystalline region between 80–180 °C, an amorphous region at around 120 °C, and a clear glass transition point at 200 °C (780 kJ/mol). Instead, the unconfined compressive mode is clearly ruled by a flow-dependent process caused by the frictional force of the interstitial fluid that flows within the cartilage matrix resulting in higher stiffness (from 12 MPa at 1 Hz to 16 MPa at 20 Hz in storage modulus). The outcomes of this study will support the development of an artificial material to mimic the thermo-mechanical behaviour of the natural cartilage of the human nose.

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