scholarly journals The Influence of Lignin Diversity on the Structural and Thermal Properties of Polymeric Microspheres Derived from Lignin, Styrene, and/or Divinylbenzene

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2847 ◽  
Author(s):  
Marta Goliszek ◽  
Beata Podkościelna ◽  
Olena Sevastyanova ◽  
Barbara Gawdzik ◽  
Artur Chabros
Keyword(s):  
Thermal Properties ◽  
Structural Characteristics ◽  
Polymer Network ◽  
Eucalyptus Grandis ◽  
Nitrogen Adsorption ◽  
Optical Microscope ◽  
Scanning Calorimetry ◽  
Promising Alternative ◽  
Synthetic Materials ◽  
The Impact

This work investigates the impact of lignin origin and structural characteristics, such as molecular weight and functionality, on the properties of corresponding porous biopolymeric microspheres obtained through suspension-emulsion polymerization of lignin with styrene (St) and/or divinylbenzene (DVB). Two types of kraft lignin, which are softwood (Picea abies L.) and hardwood (Eucalyptus grandis), fractionated by common industrial solvents, and related methacrylates, were used in the synthesis. The presence of the appropriate functional groups in the lignins and in the corresponding microspheres were investigated by attenuated total reflectance Fourier transform infrared spectroscopy (ATR/FT-IR), while the thermal properties were studied by differential scanning calorimetry (DSC). The texture of the microspheres was characterized using low-temperature nitrogen adsorption. The swelling studies were performed in typical organic solvents and distilled water. The shapes of the microspheres were confirmed with an optical microscope. The introduction of lignin into a St and/or DVB polymeric system made it possible to obtain highly porous functionalized microspheres that increase their sorption potential. Lignin methacrylates created a polymer network with St and DVB, whereas the unmodified lignin acted mainly as an eco-friendly filler in the pores of St-DVB or DVB microspheres. The incorporation of biopolymer into the microspheres could be a promising alternative to a modification of synthetic materials and a better utilization of lignin.

A study on the kinetics and thermal properties of polystyrene/diatomite nanocomposites prepared via in situ ATRP

2018 ◽  
Vol 33 (2) ◽  
pp. 180-197 ◽  
Author(s):  
Khezrollah Khezri ◽  
Yousef Fazli
Keyword(s):  
Molecular Weight ◽  
In Situ Polymerization ◽  
Structural Characteristics ◽  
Nitrogen Adsorption ◽  
Linear Increase ◽  
Size Exclusion ◽  
Scanning Calorimetry ◽  
Morphological Studies ◽  
Exclusion Chromatography

Pristine mesoporous diatomite was employed to prepare polystyrene/diatomite composites. Diatomite platelets were used for in situ polymerization of styrene by atom transfer radical polymerization to synthesize tailor-made polystyrene nanocomposites. X-Ray fluorescence spectrometer analysis and thermogravimetric analysis (TGA) were employed for evaluating some inherent properties of pristine diatomite platelets. Nitrogen adsorption/desorption isotherm is applied to examine surface area and structural characteristics of the diatomite platelets. Evaluation of pore size distribution and morphological studies were also performed by scanning and transmission electron microscopy. Conversion and molecular weight determinations were carried out using gas and size exclusion chromatography, respectively. Linear increase of ln ( M0/M) with time for all the samples shows that polymerization proceeds in a living manner. Addition of 3 wt% pristine mesoporous diatomite leads to an increase of conversion from 72% to 89%. Molecular weight of polystyrene chains increases from 11,326 g mol−1 to 14134 g mol−1 with the addition of 3 wt% pristine mesoporous diatomite; however, polydispersity index values increases from 1.13 to 1.38. Increasing thermal stability of the nanocomposites is demonstrated by TGA. Differential scanning calorimetry shows an increase in glass transition temperature from 81.9°C to 87.1°C by adding 3 wt% of mesoporous diatomite platelets.

Mechanical and Thermal Properties of Rubber Toughened Carbon Black-Filled Polyester Composite

2013 ◽  
Vol 812 ◽  
pp. 163-168 ◽  
Author(s):  
Mohd Redzuan Aein Afina ◽  
Bonnia Noor Najmi ◽  
Shuhaimen Siti Shakirah ◽  
Siti Norasmah Surip
Keyword(s):  
Thermal Properties ◽  
Carbon Black ◽  
Unsaturated Polyester ◽  
Impact Testing ◽  
Mechanical And Thermal Properties ◽  
Heat Flow Rate ◽  
Scanning Calorimetry ◽  
Rubber Toughened ◽  
Polyester Composite ◽  
The Impact

The influences of Carbon Black (CB) as filler for rubber toughened polyester composite on thermal properties were investigated, in consideration for applications such as automotive parts and integrated circuits (IC) encapsulations. The usage of CB as filler is one of the efforts in increasing and varying the use of rubber and unsaturated polyester thermoset in composite materials. Unsaturated polyester was mixed with 3% liquid natural rubber (LNR) as toughening agent and CB, which were varied from 0, 2, 4, 6, 8, and 10% using mechanical stirrer and moulded by using the open mould technique. Impact testing was conducted for mechanical property and it was found that the addition of CB increased the impact strength by 87%. Thermal properties of the composites were evaluated using a thermogravimetric analyzer (TGA) and differential scanning calorimetry (DSC). The TGA curves of the composites were quite similar, but there were slight increment in thermal stability for several CB filled composites compared to the neat polyester matrix. DSC analysis showed that all the composites were fully cured, and CB filled composites had a slower heat flow rate compared to the neat rubber toughened composite.

Effect of Intercritical Quenching on Microstructure and Mechanical Properties of Oil Casing Steel N80

2013 ◽  
Vol 395-396 ◽  
pp. 279-283
Author(s):  
Min Huang ◽  
Yu Wang ◽  
Ya Ni Zhang ◽  
Yue Wei Xie ◽  
Shuo Feng Li
Keyword(s):  
Tensile Strength ◽  
High Strength ◽  
Optical Microscope ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Scanning Calorimetry ◽  
Cross Sectional ◽  
Study Results ◽  
The Impact ◽  
The Sacrifice

In order to improve the toughness of oil casing steel N80 without the sacrifice of its original high strength, an intercritical quenching treatment was conducted under the temperature determined by a differential scanning calorimetry (DSC) analysis. Effects of intercritical quenching on the microstructure of oil casing steel N80 were characterized by means of optical microscope (OM) and scanning electron microscope (SEM). Tensile strength, reduction of cross-sectional area and microhardness were measured to evaluate the mechanical property of oil casing steel N80 after intercritical quenching treatment. The study results show that the tensile strength and microhardness of intercritical quenched oil casing steel N80 consisting of ferrite (F) and martensite (M) is slightly lower than that of tempered oil casing steel N80 composing of sorbite (S), yet which is still higher than that of full annealled oil casing steel N80 composing of pearlite (P) and a little amount of ferrite (F). In particular, the reduction of cross-sectional area of oil casing steel N80 intercritical quenched at 740°C is higher than those of tempered and full annealled. Additionally, both dimple and cleavage can be found on the impact fracture surface of N80 steel after intercritical quenching at 740°C. The toughness of oil casing steel N80 can be obviously improved by the intercritical quenching treatment at 740°C due to the formation of ferrite (F).

Mechanical and Thermal Properties of Reactable Nano-SiO2/polyoxymethylene Composites

2012 ◽  
Vol 535-537 ◽  
pp. 103-109 ◽  
Author(s):  
Xiang Min Xu ◽  
Li Ping Guo ◽  
Yu Dong Zhang ◽  
Zhi Jun Zhang
Keyword(s):  
Thermal Properties ◽  
Impact Strength ◽  
Decomposition Temperature ◽  
Silica Content ◽  
Mechanical And Thermal Properties ◽  
Scanning Calorimetry ◽  
Degradation Temperature ◽  
Melt Compounding ◽  
Air Atmosphere ◽  
The Impact

The polyoxymethylene-based composites containing reactable nano-SiO2were prepared in a twin-screw extruder by melt compounding, and mechanical and thermal properties of pure polyoxymethylene (POM) and composites were investigated. The results showed that reactable nano-SiO2could reinforce the tensile strength and Young’s modulus of composites. To the impact strength of composites, there was obvious improvement when a small amount of silica was added into POM. With the increase of silica content, the impact strength of composites showed a gradually decrease trend. It was worthy to note that reactable nano-SiO2could significantly increase the decomposition temperature of POM. When the content of reactaSubscript textble nano-SiO2was up to 5 wt%, the degradation temperature of composites could increase about 38.3°C under nSubscript textitrogen atmosphere and 43.8°C under air atmosphere, respectively, compared with pure POM. Furthermore, the differential scanning calorimetry (DSC) analysis showed that reactable nano-SiO2had a good heterogeneous nucleation capability in POM, and could increase crystallization temperature of POM, but surface structure of reactable nano-SiO2was not propitious to the growth of POM crystals, accordingly leading to the decreasing crystallinity of composites.

scholarly journals A Novel Acetylene-Functional/Silicon-Containing Benzoxazine Resin: Preparation, Curing Kinetics and Thermal Properties

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 999
Author(s):  
Qilin Mei ◽  
Honghua Wang ◽  
Danliao Tong ◽  
Jiuqiang Song ◽  
Zhixiong Huang
Keyword(s):  
Thermal Stability ◽  
Thermal Properties ◽  
Curing Kinetics ◽  
Curing Temperature ◽  
Dsc Analysis ◽  
Scanning Calorimetry ◽  
Comprehensive Performance ◽  
Acetylene Group ◽  
New Energy ◽  
The Impact

Benzoxazine resin has been paid more attention in the fields of aviation, electronics, automobiles and new energy industries because of its excellent comprehensive performance. Further application is limited, however, by shortcomings such as high brittleness and high curing temperature. Furthermore, higher thermal stability is imperiously demanded in special areas. Incorporating both an acetylene group and silicon into the benzoxazine monomer is a promising possible solution to improve the curing processability, thermal properties and toughness of benzoxazine. In this paper, an acetylene-functional/silicon-containing benzoxazine monomer was prepared by two-step synthesis, and acetylene-functional benzoxazine was also prepared as a comparison. FTIR and 1H NMR confirmed the molecular structure of acetylene-functional/silicon-containing benzoxazine. Differential scanning calorimetry (DSC) analysis showed that the initial and peak degradation temperatures of acetylene-functional/silicon-containing benzoxazine were decreased by 21 °C and 18 °C compared with acetylene-functional benzoxazine, respectively. The apparent activation energy of the curing reaction of acetylene-functional/silicon-containing benzoxazine was 83.1 kJ/mol, which was slightly lower than acetylene-functional benzoxazine (84.7 kJ/mol). TGA results showed that the acetylene-functional/silicon-containing benzoxazine had a higher thermal stability than acetylene-functional benzoxazine. The temperatures of 5% weight loss of acetylene-functional/silicon-containing benzoxazine were 380 °C in nitrogen and 485 °C in air, and the char yield at 1000 °C was 80% in nitrogen and 21% in air, respectively. The results of mechanical properties showed that the impact strength of acetylene-functional/silicon-containing benzoxazine was higher than acetylene-functional benzoxazine by 35.4%. The tensile and flexural strengths of acetylene-functional/silicon-containing benzoxazine were slightly higher than that of acetylene-functional benzoxazine.

scholarly journals Influence of the Synthesis Method on the Structural Characteristics of Novel Hybrid Adsorbents Based on Bentonite

2019 ◽  
Vol 3 (1) ◽  
pp. 18 ◽  
Author(s):  
Dariusz Sternik ◽  
Mariia Galaburda ◽  
Viktor Bogatyrov ◽  
Volodymyr Gun’ko
Keyword(s):  
Structural Characteristics ◽  
Synthesis Method ◽  
Nitrogen Adsorption ◽  
Inert Atmosphere ◽  
Scanning Calorimetry ◽  
Resorcinol Formaldehyde ◽  
X Ray Scattering ◽  
Adsorption Desorption ◽  
Tga And Dsc ◽  
Thermal Stability Of

New hybrid composite materials were prepared by polymerization of resorcinol–formaldehyde resins in the presence of bentonite with various contents of polymer and water, and then exposed to pyrolysis in an inert atmosphere at 800 °C. The influence of the filler and synthesis method on the morphological, textural and structural characteristics has been described. The materials were characterized using low temperature nitrogen adsorption–desorption, small angle X-ray scattering, scanning electron microscopy, Raman spectroscopy, differential scanning calorimetry (DSC), and thermogravimetry analysis (TGA). The maximal values of the specific surface area of organo-bentonite and carbonized samples were 254 and 200 m2/g, respectively, which is much larger than that of the initial bentonite. The TGA and DSC experiments showed changes in the thermal stability of samples depending on their composition. The obtained data could provide a better understanding of the principles of preparing hybrid bentonite-containing composites that may provide an additional incentive to develop advanced technologies.

scholarly journals Analysis of Ageing Processes of Semi-Crystalline Materials

2020 ◽  
Vol 57 (3) ◽  
pp. 41-51
Author(s):  
Aleksandra Kalwik ◽  
Przemyslaw Postawa ◽  
Marcin Nabialek
Keyword(s):  
Differential Scanning Calorimetry ◽  
Test Chamber ◽  
Optical Microscope ◽  
Polymer Materials ◽  
Scanning Calorimetry ◽  
Crystalline Materials ◽  
Fluorescent Lamps ◽  
Uv Ageing ◽  
Ageing Processes ◽  
The Impact

The article presents the influence of accelerated UV ageing on the structural properties of selected polymer materials. In this study, 3 types of materials from a group of thermoplastics known as PP30T, PE, POM were used. The test samples were prepared by injection moulding. In turn, an accelerated UV ageing process (600 h) was carried out in the UV Test chamber with fluorescent lamps characterized by a wavelength of 313 nm. Changes in the structure of the tested materials were observed by using an optical microscope. Measurements of gloss on the surface of primary samples that were exposed to UV rays were also taken. In addition, the structure of primary and aged samples was tested by differential scanning calorimetry (DSC). The conducted studies have demonstrated the impact of UV radiation on the changes in the surface layer of tested materials.

Effect of Mesoporous Diatomite Particles on the Kinetics of SR&NI ATRP of Styrene and Butyl Acrylate

2018 ◽  
Vol 0 (0) ◽  
Author(s):  
Khezrollah Khezri ◽  
Moosa Ghasemi ◽  
Yousef Fazli
Keyword(s):  
Molecular Weight ◽  
Butyl Acrylate ◽  
Structural Characteristics ◽  
Nitrogen Adsorption ◽  
Size Exclusion ◽  
Scanning Calorimetry ◽  
Morphological Studies ◽  
Exclusion Chromatography ◽  
Adsorption Desorption ◽  
Mesoporous Diatomite Nanoplatelets

Abstract Mesoporous diatomite particles were employed to prepare different poly(styrene-co-butyl acrylate)/diatomite nanocomposites. Diatomite nanoplatelets were used for in situ copolymerization of styrene and butyl acrylate by SR&NI ATRP to synthesize well-defined poly(styrene-co-butyl acrylate) nanocomposites. Nitrogen adsorption/desorption isotherm is applied to examine surface area and structural characteristics of the diatomite nanoplatelets. Evaluation of pore size distribution and morphological studies were also performed by SEM and TEM. Conversion and molecular weight determinations were carried out using gas and size exclusion chromatography respectively. Addition of 3 wt% pristine mesoporous diatomite nanoplatelets leads to increase of conversion from 73 to 89%. Molecular weight of poly(styrene-co-butyl acrylate) chains increases from 17,115 to 20,343 g·mol−1 by addition of 3 wt% pristine mesoporous diatomite; however, polydispersity index values increases from 1.14 to 1.37. Increasing thermal stability of the nanocomposites is demonstrated by TGA. Differential scanning calorimetry shows an increase in glass transition temperature from 35.26 to 39.61°C by adding 3 wt% of mesoporous diatomite nanoplatelets.

Crystallization, structural and mechanical properties of PA6/PC/NBR ternary blends: effect of NBR-g-GMA compatibilizer and organoclay

2017 ◽  
Vol 24 (5) ◽  
pp. 669-678 ◽  
Author(s):  
Masoumeh Delkash ◽  
Ghasem Naderi ◽  
Razi Sahraieyan ◽  
Elnaz Esmizadeh
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Tensile Modulus ◽  
Optical Microscope ◽  
Ternary Blend ◽  
Butadiene Rubber ◽  
Ternary Blends ◽  
Scanning Calorimetry ◽  
X Ray ◽  
The Impact

AbstractTernary blends based on polyamide 6 (PA6)/acrylonitrile-butadiene rubber (NBR)/polycarbonate (PC) were prepared by melt compounding via extrusion process. The effect of organoclay (OC), compatibilizer, and blend ratio was investigated on structural and mechanical properties of the blend. The effect of OC and compatibilizer studied on crystallization temperature, melting temperature, and crystallinity of PA6/NBR/PC ternary blends was studied by differential scanning calorimetry. Improvement in the crystal structure of compatibilized blend compared to unfilled blend was observed by polarized optical microscope. Dispersion of OC into PA6/NBR/PC ternary blends was done by X-ray diffraction, transmission electron microscopy, and scanning electron microscopy (SEM)/energy-dispersive X-ray. The results confirmed the exfoliation of OC particles into the polymer matrix. The improvement in yield stress and tensile modulus of the ternary blend was observed in the presence of OC. The impact strength showed an increase using NBR-glycidyl methacrylate-grafted (g-GMA) to prepare compatibilized PA6/NBR/PC ternary blend.

scholarly journals Mechanical and Thermal Properties of PLA Biocomposites Reinforced by Coir Fibers

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Zhihui Sun ◽  
Li Zhang ◽  
Duoping Liang ◽  
Wei Xiao ◽  
Jing Lin
Keyword(s):  
Thermal Properties ◽  
Impact Strength ◽  
Fiber Content ◽  
Minor Effect ◽  
Mechanical And Thermal Properties ◽  
Coir Fiber ◽  
Mixed Solution ◽  
Scanning Calorimetry ◽  
Coir Fibers ◽  
The Impact

In this work, polylactic acid (PLA) biocomposites reinforced with short coir fibers were fabricated using a corotating twin-screw extruder and injection molding machine. Short coir fibers were treated by mixed solution including hydrogen peroxide and sodium hydroxide to improve the adhesion between fibers and PLA matrix. The effects of treated coir fiber content (1, 3, 5, and 7 wt%) on tensile, impact, thermal properties, and surface morphology of PLA biocomposites were investigated. The best impact strength results were obtained for 3 wt% PLA/treated coir fiber biocomposites, where the impact strength was increased by approximately 28% compared to the neat PLA. The tensile modulus of PLA biocomposites was increased by increasing the treated coir fiber content. These results were confirmed by morphological structure analysis. Differential scanning calorimetry (DSC) results demonstrated a minor effect of the treated coir fiber on thermal behavior of PLA resin. Thermogravimetry analysis (TGA) demonstrated that the thermal stability of the PLA/treated coir fiber biocomposites was reduced by the incorporation of treated coir fiber.

Sign in / Sign up

Export Citation Format

Share Document