Further understanding the response mechanism of lignin content to bonding properties of lignocellulosic fibers by their deformation behavior

RSC Advances ◽  
2016 ◽  
Vol 6 (110) ◽  
pp. 109211-109217 ◽  
Author(s):  
Zhiqiang Li ◽  
Hongjie Zhang ◽  
Xin Wang ◽  
Fengshan Zhang ◽  
Xiaoliang Li
Keyword(s):  
Deformation Behavior ◽  
Lignin Content ◽  
Response Mechanism ◽  
Bulk Properties ◽  
Lignocellulosic Fibers ◽  
Bonding Properties

The deformation behavior of lignocellulosic fibers was used to further understand the contradiction between their bonding and bulk properties.

scholarly journals The Effects of Unbleached and Bleached Nanocellulose on the Thermal and Flammability of Polypropylene-Reinforced Kenaf Core Hybrid Polymer Bionanocomposites

Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 116
Author(s):  
Fatimah Athiyah Sabaruddin ◽  
M.T. Paridah ◽  
S. M. Sapuan ◽  
R. A. Ilyas ◽  
Seng Hua Lee ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Lignin Content ◽  
Hybrid Polymer ◽  
Residual Lignin ◽  
Flame Resistance ◽  
Melt Mixing ◽  
Kenaf Core ◽  
The Poor ◽  
Bonding Properties ◽  
Thermal Stability Of

The thermal, thermo-mechanical and flammability properties of kenaf core hybrid polymer nanocomposites reinforced with unbleached and bleached nanocrystalline cellulose (NCC) were studied. The studied chemical composition found that unbleached NCC (NCC-UB) had 90% more lignin content compared to bleached NCC (NCC-B). Nanocelluloses were incorporated within polypropylene (PP) as the matrix, together with kenaf core as a main reinforcement and maleic anhydride grafted polypropylene (MAPP) as a coupling agent via a melt mixing compounding process. The result showed that the thermal stability of the nanocomposites was generally affected by the presence of lignin in NCC-UB and sulfate group on the surface of NCC-B. The residual lignin in NCC-UB appeared to overcome the poor thermal stability of the composites that was caused by sulfation during the hydrolysis process. The lignin helped to promote the late degradation of the nanocomposites, with the melting temperature occurring at a relatively higher temperature of 219.1 °C for PP/NCC-UB, compared to 185.9 °C for PP/NCC-B. Between the two types of nanocomposites, PP/NCC-B had notably lower thermo-mechanical properties, which can be attributed to the poor bonding and dispersion properties of the NCC-B in the nanocomposites blend. The PP/NCC-UB showed better thermal properties due to the effect of residual lignin, which acted as a compatibilizer between NCC-UB and polymer matrix, thus improved the bonding properties. The residual lignin in PP/NCC-UB helped to promote char formation and slowed down the burning process, thus increasing the flame resistance of the nanocomposites. Overall, the residual lignin on the surface of NCC-UB appeared to aid better stability on the thermal and flammability properties of the nanocomposites.

scholarly journals Deformation behavior of wet lignocellulosic fibers

Holzforschung ◽  
2007 ◽  
Vol 61 (3) ◽  
pp. 261-266 ◽  
Author(s):  
Robert M. Lowe ◽  
Derek H. Page ◽  
John F. Waterhouse ◽  
Jeff Hsieh ◽  
Naveen Cheluka ◽  
...  
Keyword(s):  
Deformation Behavior ◽  
Step Height ◽  
Pulp Fibers ◽  
Lignocellulosic Fibers ◽  
Light Interference ◽  
Glass Slides ◽  
Main Effect ◽  
Wet Pressing ◽  
Analysis Computer ◽  
Dilute Suspension

Abstract The deformation behavior of wet lignocellulosic fibers was examined by applying a dilute suspension of dyed pulp fibers to a filter paper and then wet pressing the fibers onto glass slides. The geometry of single fiber crossing was determined using light interference and an image analysis computer program. The effects of pulp type, refining, wet pressing, drying and bleaching on the deformation behavior of pulp fibers were explored. The main effect of refining fibers was to reduce the step height for fiber-fiber crossings for both bleached and unbleached pulps by increasing the tendency of the cell wall to collapse and deform. All the pulps and treatments investigated maintained a relatively constant value for the step height/free span ratio.

scholarly journals Different Deformation Behavior Between ZrO2 and Y2O3 Particles in Dispersion Strengthened Pt-20Rh Alloys

2020 ◽  
Author(s):  
Ziyang Wang ◽  
Xi Wang ◽  
Futao Liu ◽  
Faping Hu ◽  
Hao Chen ◽  
...  
Keyword(s):  
Deformation Behavior ◽  
Rolling Direction ◽  
Hot Forging ◽  
Spherical Shape ◽  
Normal Direction ◽  
Interface Bonding ◽  
Ion Milling ◽  
Transmission Electron ◽  
Bonding Properties ◽  
Pure Metals

Pt-20Rh strengthened by oxides of Zr and Y were prepared by solidification of Pt-Rh-(Zr)-Y powder which had been internally oxidized. After forging, rolling and annealing, the 1 mm plates were obtained. Then the plates from rolling-normal direction were mechanically grinded to 50-70 μm, followed by Ar+ ion milling until a hole appeared on the center of the foil to obtain samples which characterized by transmission electron microscopy (TEM), combined with thermodynamic analysis, the existence of spherical ZrO2 and Y2O3 particles was verified, Pt and Rh still existed as a form of pure metals at the same time. It was found that the deformation behavior of ZrO2 and Y2O3 particles was quite different during processing, where the former basically maintain their spherical shape and were bonded tightly to matrix, while the latter were compressed along normal direction and form two cracks on the both sides of Y2O3 particles along rolling direction. The differences in hardness and interface bonding properties of these two types of particles are supposed to be the main causes of different deformation behavior during hot forging and cold rolling.

Plastic deformation of θ ' in Al-4%Cu alloy

1978 ◽  
Vol 36 (1) ◽  
pp. 576-577
Author(s):  
Shrikant P. Bhat
Keyword(s):  
Deformation Behavior ◽  
Room Temperature ◽  
Electron Microscopic Observation ◽  
Bulk Alloy ◽  
Electron Microscopic ◽  
Cu Alloy ◽  
Cu Alloys ◽  
Orowan Mechanism ◽  
The Subject ◽  
Cyclic Straining

deformation behavior of Al-Cu alloys aged to contain θ ' has been the subject of many investigations (e.g., Ref. 1-5). Since θ ' is strong and hard, dislocations bypass θ ' plates (Orowan mechanism) at low strains. However, at high strains the partially coherent θ ' plates are probably sheared, although the mechanism is complex, depending on the form of deformation. Particularly, the cyclic straining of the bulk alloy is known to produce gross bends and twists of θ '. However, no detailed investigation of the deformation of θ ' has yet been reported; moreover, Calabrese and Laird interpreted the deformation of θ ' as largely being elastic.During an investigation of high temperature cyclic deformation, the detailed electron-microscopic observation revealed that, under reversed straining conditions, θ ' particles are severely distorted--bent and twisted depending on the local matrix constraint. A typical electronmicrograph, showing the twist is shown in Fig. 1. In order to establish whether the deformation is elastic or plastic, a sample from a specimen cycled at room temperature was heated inside the microscope and the results are presented in a series of micrographs (Fig. 2a-e).

Observation of secondary slip systems in tungsten bicrystals

1984 ◽  
Vol 42 ◽  
pp. 478-479
Author(s):  
J. R. Fekete ◽  
R. Gibala
Keyword(s):  
Stress Field ◽  
Grain Boundaries ◽  
Deformation Behavior ◽  
Stress Axis ◽  
Polycrystalline Materials ◽  
Slip Systems ◽  
Metallic Materials ◽  
Twist Boundary ◽  
Secondary Slip ◽  
Plane Normal

The deformation behavior of metallic materials is modified by the presence of grain boundaries. When polycrystalline materials are deformed, additional stresses over and above those externally imposed on the material are induced. These stresses result from the constraint of the grain boundaries on the deformation of incompatible grains. This incompatibility can be elastic or plastic in nature. One of the mechanisms by which these stresses can be relieved is the activation of secondary slip systems. Secondary slip systems have been shown to relieve elastic and plastic compatibility stresses. The deformation of tungsten bicrystals is interesting, due to the elastic isotropy of the material, which implies that the entire compatibility stress field will exist due to plastic incompatibility. The work described here shows TEM observations of the activation of secondary slip in tungsten bicrystals with a [110] twist boundary oriented with the plane normal parallel to the stress axis.

Silicification of wood-cell walls

1994 ◽  
Vol 52 ◽  
pp. 428-429
Author(s):  
S. E. Keckler ◽  
D. M. Dabbs ◽  
N. Yao ◽  
I. A. Aksay
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Cell Walls ◽  
Lignin Content ◽  
Resin Composite ◽  
Middle Lamella ◽  
Cellulose Fibers ◽  
Complex Structures ◽  
Rich Region ◽  
Inorganic Precursors

Cellular organic structures such as wood can be used as scaffolds for the synthesis of complex structures of organic/ceramic nanocomposites. The wood cell is a fiber-reinforced resin composite of cellulose fibers in a lignin matrix. A single cell wall, containing several layers of different fiber orientations and lignin content, is separated from its neighboring wall by the middle lamella, a lignin-rich region. In order to achieve total mineralization, deposition on and in the cell wall must be achieved. Geological fossilization of wood occurs as permineralization (filling the void spaces with mineral) and petrifaction (mineralizing the cell wall as the organic component decays) through infiltration of wood with inorganics after growth. Conversely, living plants can incorporate inorganics into their cells and in some cases into the cell walls during growth. In a recent study, we mimicked geological fossilization by infiltrating inorganic precursors into wood cells in order to enhance the properties of wood. In the current work, we use electron microscopy to examine the structure of silica formed in the cell walls after infiltration of tetraethoxysilane (TEOS).

Transformation and Deformation Behavior in Sputter-Deposited Ti-Ni-Cu Thin Films

1995 ◽  
Vol 05 (C8) ◽  
pp. C8-689-C8-694 ◽  
Author(s):  
T. Hashinaga ◽  
S. Miyazaki ◽  
T. Ueki ◽  
H. Horikawa
Keyword(s):  
Thin Films ◽  
Deformation Behavior ◽  
Sputter Deposited

Responses of Platelets to Strains of Streptococcus sanguis: Findings in Healthy Subjects, Bernard-Soulier, Glanzmann’s, and Collagen-Unresponsive Patients

1987 ◽  
Vol 57 (02) ◽  
pp. 222-225 ◽  
Author(s):  
A H Soberay ◽  
M C Herzberg ◽  
J D Rudney ◽  
H K Nieuwenhuis ◽  
J J Sixma ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Healthy Subjects ◽  
Normal Subjects ◽  
Membrane Glycoprotein ◽  
Response Mechanism ◽  
Platelet Response ◽  
Induce Platelet Aggregation ◽  
Streptococcus Sanguis ◽  
Lag Times ◽  
Bernard Soulier Syndrome

SummaryThe ability of endocarditis and dental strains of Streptococcus sanguis to induce platelet aggregation in plasma (PRP) from normal subjects were examined and compared to responses of PRP with known platelet membrane glycoprotein (GP) and response defects. S. sanguis strains differed in their ability to induce normal PRPs to aggregate. Strains that induced PRP aggregation in more than 60% of donors were significantly faster agonists (mean lag times to onset of aggregation less than 6 min) than those strains inducing response in PRPs of fewer than 60% of donors.Platelets from patients with Bernard-Soulier syndrome aggregated in response to strains of S. sanguis. In contrast, platelets from patients with Glanzmann’s thrombasthenia and from a patient with a specific defect in response to collagen were unresponsive to S. sanguis. These observations show that GPIb and V are not essential, but GPIIb-IIIa and GPIa are important in the platelet response mechanism to S. sanguis. Indeed, the data suggests that the platelet interaction mechanisms of S. sanguis and collagen may be similar.

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