Rheology of moso bamboo stem determined by DMA in ethylene glycol

Holzforschung ◽  
2019 ◽  
Vol 73 (2) ◽  
pp. 171-179
Author(s):  
Fangli Sun ◽  
Guigui Wan ◽  
Yan Zhang ◽  
Charles E. Frazier

AbstractThe basic properties of moso bamboo (MB) were determined according to the International Organization for Standardization (ISO) standards and its rheological behavior was studied by dynamic mechanical analysis (DMA) in the tensile torsion stress mode after plasticization with ethylene glycol (EG). Results show that the density and the apparent lignin content of MB increases and the degree of crystallinity decreases with increasing age. Storage modulus (G′) increases from 1- to 3-year-old MB, and then decreases again with age. When the bamboo culm with the inner and outer surface planed off was divided into three layers in the radial direction, the G′ of the outer layer was always higher than that of the middle and inner layers. The glass transition temperature (Tg) of MB plasticized with EG is about 10°C lower than the water plasticized ones, and the Tg of the outer and inner layers was nearly 1–2°C higher than that of the middle layer. The overall trend of basic properties and rheological behaviors seems to exhibit a discontinuity at 3 years, which might reflect the growth of MB and mainly the thickening of cell walls.

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Emi Govorčin Bajsić ◽  
Vesna Rek ◽  
Ivana Ćosić

The effect of the addition of talc on the morphology and thermal properties of blends of thermoplastic polyurethane (TPU) and polypropylene (PP) was investigated. The blends of TPU and PP are incompatible because of large differences in polarities between the nonpolar crystalline PP and polar TPU and high interfacial tensions. The interaction between TPU and PP can be improved by using talc as reinforcing filler. The morphology was observed by means of scanning electron microscopy (SEM). The thermal properties of the neat polymers and unfilled and talc filled TPU/PP blends were studied by using dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The addition of talc in TPU/PP blends improved miscibility in all investigated TPU/T/PP blends. The DSC results for talc filled TPU/PP blends show that the degree of crystallinity increased, which is due to the nucleating effect induced by talc particles. The reason for the increased storage modulus of blends with the incorporation of talc is due to the improved interface between polymers and filler. According to TGA results, the addition of talc enhanced thermal stability. The homogeneity of the talc filled TPU/PP blends is better than unfilled TPU/PP blends.


Polymers ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1013 ◽  
Author(s):  
Xuan Wang ◽  
Yuan Jia ◽  
Zhen Liu ◽  
Jiaojiao Miao

Poly(lactic acid) (PLA)/lignin-containing cellulose nanofibrils (L-CNFs) composite films with different lignin contents were produced bythe solution casting method. The effect of the lignin content on the mechanical, thermal, and crystallinity properties, and PLA/LCNFs interfacial adhesion wereinvestigated by tensile tests, thermogravimetric analysis, differential scanning calorimetry (DSC), dynamic mechanical analysis, Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The tensile strength and modulus of the PLA/9-LCNFs (9 wt % lignin LCNFs) composites are 37% and 61% higher than those of pure PLA, respectively. The glass transition temperature (Tg) decreases from 61.2 for pure PLA to 52.6 °C for the PLA/14-LCNFs (14 wt % lignin LCNFs) composite, and the composites have higher thermal stability below 380 °C than pure PLA. The DSC results indicate that the LCNFs, containing different lignin contents, act as a nucleating agent to increase the degree of crystallinity of PLA. The effect of the LCNFs lignin content on the PLA/LCNFs compatibility/adhesion was confirmed by the FTIR, SEM, and Tg results. Increasing the LCNFs lignin content increases the storage modulus of the PLA/LCNFs composites to a maximum for the PLA/9-LCNFs composite. This study shows that the lignin content has a considerable effect on the strength and flexibility of PLA/LCNFs composites.


2019 ◽  
Vol 20 (12) ◽  
Author(s):  
Herman Siruru ◽  
WASRIN SYAFII ◽  
I NYOMAN J. WISTARA ◽  
GUSTAN PARI

Abstract. Siruru H, Syafii W, Wistara I. N. J, Pari G. 2019. Characteristics of Metroxylon rumphii (pith and bark waste) from Seram Island, Maluku, Indonesia. Biodiversitas 20: 3517-3526. Sago (Metroxylon rumphii Martius) pith waste (SPW) and sago bark waste (SBW) are lignocellulosic materials that can be used for various needs directly or indirectly. It is necessary to understand SPW and SBW characteristics to maximize their utilization. In this study, we analyzed the proximate, ultimate, and crystallinity by XRD, the functional groups by FTIR, morphology by SEM, and the derivate analysis of hot water-soluble extractives by GCMS. The contents of SPW and SBW hot-water soluble extractive, lignin, and holocellulose were 57.7 and 4.9%, 6.1 and 29.4%, and 45.74 and 66.74%, respectively. The volatile matter, ash content, silica, fixed carbon, C, H, and O contents of the SPW and SBW were 81.48 and 84.56%, 1.30 and 3.04%, 1.25% and 2.03, 12.77 and 18.06%, 37.93 and 44.64%, 6.37 and 6.49%, and 47.75 and 51.10%, respectively. The degree of crystallinity of SPW was 15.04%, while that of SBW was 47.28%, where both have a monoclinic structure with the main peak by 2Ɵ 16° and 26°. SPW and SBW contained several minerals such as silica, boron, sulfur, and phosphorus. The surface morphology of the SPW was porous with a small diameter and thin cell wall, while that of SBW was covered by minerals. Nitrogen, alcohol, and sugar group compounds were found more in SPW, whereas phenol compound was more in SBW. SBW has high lignin content and SPW has a very large amount of hot water-soluble extractive.


Buildings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 240
Author(s):  
Vladimir Kotlyar ◽  
Victoria Pishchulina ◽  
Alexey N. Beskopylny ◽  
Besarion Meskhi ◽  
Yury Popov ◽  
...  

Determining the age of ancient architectural and cultural monuments is a significant scientific problem. An approach based on the transformation of portlandite into calcite and subsequent recrystallization of calcite is considered, which allows for estimating the relative age of ancient brickworks for local groups of historic buildings based on the results of diffraction studies of powder samples of carbonate mortars and measurements of samples with a known age. This article presents the results of the study of lime mortars of ancient brickwork. Under natural conditions, the process of transformation of portlandite into calcite takes from 100 to 200 years. The rate of this process is influenced by temperature, humidity, peculiarities of interaction with carbon dioxide contained in the air, etc. Examples show that portlandite is completely transformed into calcite in masonry mortars of the 18th century and that portlandite is not found in older mortars. It was determined that after the transformation of portlandite into calcite, an increase in the degree of recrystallization of calcite is observed, which manifests itself in powder diffraction patterns in the relative broadening of the diffraction peak of calcite hkl 104. In a detailed study, an estimate of the peak width at half maximum (FWHM) associated with the degree of crystallinity is effective. The actual data are given, which show that in older lime mortars the degree of recrystallization of calcite is higher than in younger ones. This fact makes it possible to indirectly determine the relative age of brickwork and masonry of various buildings of architectural heritage, which is especially relevant for the objects with the use of lime mortars of the northern provinces of the Byzantine Oecumene and other periods of various cultures.


2013 ◽  
Vol 864-867 ◽  
pp. 751-754 ◽  
Author(s):  
Andrey Askadskii ◽  
Marina Popova ◽  
Tatyana Matseevich ◽  
Elena Kurskaya

The influence of the degree of crystallinity of polymers on the glass transition temperature Tg of their amorphous domains is quantitatively analyzed. The analysis is made based on the Mandelkerns ideas [ concerning the restrictive effect of crystallization on the mobility of macromolecules within the amorphous domains. At low degrees of crystallinity, Tg of amorphous domains slowly increases, and then increases much faster at high degrees of crystallinity.


2021 ◽  
Vol 1028 ◽  
pp. 326-330
Author(s):  
Otong Nurhilal ◽  
Sahrul Hidayat ◽  
Dadan Sumiarsa ◽  
Maykel Manawan ◽  
Risdiana

The quality of the carbon material for application of electrodes in the battery is indicated by its ability to intercalate ions, atoms or molecules. Graphite is a carbon material with good intercalation capability. In this research, a carbon material in the form of activated charcoal produced from biomass of water hyacinth has been prepared, which is carbonized at various temperatures of 400, 500, and 600 °C with three different activators of ZnCl2, KOH and H3PO4. The activated charcoal will be used as a cathode composite in lithium sulfur batteries. To determine the quality of the activated charcoal, the structure properties of activated charcoal were characterized using X-ray diffraction (XRD). Several parameters that are determined from XRD data included the degree of crystallinity, and the degree of graphitization (Y). The degree of crystallinity was found in the ranges between 5.56 and 12.6%, where activated charcoal was dominated by amorphous structures. The value of the degree of graphitization was about 36%.


2021 ◽  
Vol 5 ◽  
pp. 60-69
Author(s):  
V. N. Vasilets ◽  
◽  
A. P. Pankina ◽  
E. A. Nemets ◽  
V. Yu. Belov ◽  
...  

Structural and morphological changes in the films of poly(oxybirutyrate-co-oxyvalerate) (P(OB-OV)) with poly-e-caprolactone (PCL) were studied by IR spectroscopy, DSC, and scanning electron microscopy during accelerated oxidative degradation under tests in Fenton reagent. It is shown by the DSC method that the phase separation of the P(OB-OV) and PCL components is observed in the initial mixture. The melting of various phases of P(OB-OV) is observed at temperatures of 147 °C and 157 °C, and PCL melts at a temperature of 61 °C. The degree of crystallinity of P(OB-OV) and PCL in the mixture is 67 % and 50 %, respectively. It was found that the degradation of poly(oxybirutyrate-co-oxyvalerate) prevails during incubation of composite samples in Fenton solution for 2 to 12 weeks. By changing the ratio of the components, it is possible to significantly change the rate of oxidative degradation, the molecular weight and the degree of crystallinity of the polymer composite material P(OB-OV):PCL.


2018 ◽  
Vol 773 ◽  
pp. 82-87
Author(s):  
Nichaphat Passornraprasit ◽  
Wanpen Tachaboonyakiat

The aim of this study was to investigate the effect of chitin whisker (CW) to the crystallization of polylactide (PLA) nanocomposite films. CW which obtained from acidolysis reaction was compounded with PLA pellets into nanocomposite films by cast film extrusion. The morphology and crystallinity of CW were observed by TEM and XRD, illustrated that the dimension of whisker was affected by hydrolysis time. Increasing of hydrolysis time, the length of whisker was more regular with narrower distribution. Moreover, the crystallinity of whisker was obviously increased after acid hydrolysis. The nanocomposite film showed rough surface compared to pure PLA film due to some agglomeration of nanoparticles. However, CW and PLA were well-mixed with no phase separation. The introduction of 0.1 phr of CW decrease cold-crystallization temperature (Tcc) from about 121 °C to 118 °C and also increase the degree of crystallinity around 10%. There was no difference of thermal transition temperature between pure PLA and nanocomposite films with the addition of CW more than 0.1 phr which inspected by DSC. Despite the transition temperature express insignificantly different, the degree of crystallinity of nanocomposite was increase, indicating that chitin whisker would induce the crystallinity of PLA.


Sign in / Sign up

Export Citation Format

Share Document