scholarly journals Synthesis and Characterization of Block Copolymers of Poly(silylene diethynylbenzen) and Poly(silylene dipropargyl aryl ether)

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1511
Author(s):  
Man Gao ◽  
Chengyuan Shang ◽  
Jixian Li ◽  
Gang Han ◽  
Junkun Tang ◽  
...  
Keyword(s):  
Block Copolymers ◽  
Diphenyl Ether ◽  
Mechanical Analysis ◽  
Mechanical Tests ◽  
Aryl Ether ◽  
Scanning Calorimetry ◽  
Comprehensive Properties ◽  
Structures And Properties ◽  
Grignard Reactions

Poly(silylene diethynylbenzene)–b–poly(silylene dipropargyloxy diphenyl propane) copolymer (ABA-A), poly(silylene diethynylbenzene)–b–poly(silylene dipropargyloxy diphenyl ether) copolymer (ABA-O), and a contrast poly(silylene diethynylbenzene) with equivalent polymerization degree were synthesized through Grignard reactions. The structures and properties of the copolymers were investigated via hydrogen nuclear magnetic resonance, Fourier transform infrared spectroscopy, Haake torque rheometer, differential scanning calorimetry, dynamic mechanical analysis, thermogravimetric analysis and mechanical tests. The results show that the block copolymers possess comprehensive properties, especially good processability and good mechanical properties. The processing windows of these copolymers are wider than 58 °C. The flexural strength of the cured ABA-A copolymer reaches as high as 40.2 MPa. The degradation temperatures at 5% weight loss (Td5) of the cured copolymers in nitrogen are all above 560 °C.

Light-cured dental composites characterization by Electron Microscopy

1990 ◽  
Vol 48 (4) ◽  
pp. 428-429
Author(s):  
B. M. Culbertson ◽  
M. L. Devinev ◽  
E. C. Kao
Keyword(s):  
Electron Microscopy ◽  
Mechanical Analysis ◽  
Service Performance ◽  
Dental Composite ◽  
Dental Composites ◽  
Neat Resin ◽  
Scanning Calorimetry ◽  
Research Meeting ◽  
Formulation Variables

The service performance of current dental composite materials, such as anterior and posterior restoratives and/or veneer cements, needs to be improved. As part of a comprehensive effort to find ways to improve such materials, we have launched a broad spectrum study of the physicochemical and mechanical properties of photopolymerizable or visible light cured (VLC) dental composites. The commercially available VLC materials being studied are shown in Table 1. A generic or neat resin VLC system is also being characterized by SEM and TEM, to more fully understand formulation variables and their effects on properties.At a recent dental research meeting, we reported on the differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) characterization of the materials in Table 1. It was shown by DSC and DMA that the materials are substantially undercured by commonly used VLC techniques. Post curing in an oral cavity or a dry environment at 37 to 50°C for 7 or more hours substantially enhances the cure of the materials.

Star-shaped arylacetylene resins derived from silicon

2020 ◽  
Vol 40 (8) ◽  
pp. 676-684
Author(s):  
Niping Dai ◽  
Junkun Tang ◽  
Manping Ma ◽  
Xiaotian Liu ◽  
Chuan Li ◽  
...  
Keyword(s):  
High Performance ◽  
Room Temperature ◽  
Mechanical Test ◽  
Flexural Modulus ◽  
Mechanical Analysis ◽  
Reinforced Composites ◽  
Scanning Calorimetry ◽  
Chemical Structures ◽  
Structures And Properties ◽  
High Performance Resin

AbstractStar-shaped arylacetylene resins, tris(3-ethynyl-phenylethynyl)methylsilane, tris(3-ethynyl-phenylethynyl) phenylsilane, and tris (3-ethynyl-phenylethynyl) silane (TEPHS), were synthesized through Grignard reaction between 1,3-diethynylbenzene and three types of trichlorinated silanes. The chemical structures and properties of the resins were characterized by means of nuclear magnetic resonance, fourier-transform infrared spectroscopy, Haake torque rheomoter, differential scanning calorimetry, dynamic mechanical analysis, mechanical test, and thermogravimetric analysis. The results show that the melt viscosity at 120 °C is lower than 150 mPa⋅s, and the processing windows are as wide as 60 °C for the resins. The resins cure at the temperature as low as 150 °C. The good processabilities make the resins to be suitable for resin transfer molding. The cured resins exhibit high flexural modulus and excellent heat-resistance. The flexural modulus of the cured TEPHS at room temperature arrives at as high as 10.9 GPa. Its temperature of 5% weight loss (Td5) is up to 697 °C in nitrogen. The resins show the potential for application in fiber-reinforced composites as high-performance resin in the field of aviation and aerospace.

scholarly journals Preparation and Characterization of Talc Filled Thermoplastic Polyurethane/Polypropylene Blends

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Emi Govorčin Bajsić ◽  
Vesna Rek ◽  
Ivana Ćosić
Keyword(s):  
Thermal Properties ◽  
Thermoplastic Polyurethane ◽  
Mechanical Analysis ◽  
Degree Of Crystallinity ◽  
Scanning Calorimetry ◽  
Polypropylene Blends ◽  
Pp Blends ◽  
The Degree Of Crystallinity ◽  
Better Than

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.

Enhancing the Thermal and Mechanical Characteristics of Polyvinyl Alcohol (PVA)-Hemp Protein Particles (HPP) Composites

2021 ◽  
Vol 36 (2) ◽  
pp. 137-143
Author(s):  
S. A. Awad
Keyword(s):  
Mechanical Properties ◽  
Elevated Temperatures ◽  
Composite Films ◽  
Tensile Tests ◽  
Mechanical Analysis ◽  
Decomposition Temperature ◽  
Scanning Calorimetry ◽  
Solution Casting Method ◽  
Protein Particles

Abstract This paper aims to describe the thermal, mechanical, and surface properties of a PVA/HPP blend whereby the film was prepared using a solution casting method. The improvements in thermal and mechanical properties of HPP-based PVA composites were investigated. The characterization of pure PVA and PVA composite films included tensile tests, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The results of TGA and DSC indicated that the addition of HPP increased the thermal decomposition temperature of the composites. Mechanical properties are significantly improved in PVA/HPP composites. The thermal stability of the PVA composite increased with the increase of HPP filler content. The tensile strength increased from 15.74 ± 0.72 MPa to 27.54 ± 0.45 MPa and the Young’s modulus increased from 282.51 ± 20.56 MPa to 988.69 ± 42.64 MPa for the 12 wt% HPP doped sample. Dynamic mechanical analysis (DMA) revealed that at elevated temperatures, enhanced mechanical properties because of the presence of HPP was even more noticeable. Morphological observations displayed no signs of agglomeration of HPP fillers even in composites with high HPP loading.

Warpage Characterization of Molded Wafer for Fan-Out Wafer-Level Packaging

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Hsien-Chie Cheng ◽  
Yan-Cheng Liu
Keyword(s):  
Measurement Data ◽  
Mechanical Analysis ◽  
Volumetric Shrinkage ◽  
Heat Of Reaction ◽  
Wafer Level ◽  
Molding Process ◽  
Scanning Calorimetry ◽  
Molding Compound ◽  
Wafer Level Packaging

Abstract This study presents a comprehensive assessment of the process-induced warpage of molded wafer for chip-first, face-down fan-out wafer-level packaging (FOWLP) during the fan-out fabrication process. A process-dependent simulation methodology is introduced, which integrates nonlinear finite element (FE) analysis and element death-birth technique. The effects of the cure-dependent volumetric shrinkage, geometric nonlinearity, and gravity loading on the process-induced warpage are examined. The study starts from experimental characterization of the temperature-dependent material properties of the applied liquid type epoxy molding compound (EMC) system through dynamic mechanical analysis (DMA) and thermal mechanical analysis. Furthermore, its cure state (heat of reaction and degree of cure (DOC)) during the compression molding process (CMP) is measured by differential scanning calorimetry (DSC) tests. Besides, the cure dependent-volumetric (chemical) shrinkages of the EMC system after the in-mold cure (IMC) and postmold cure (PMC) are experimentally determined by which the volumetric shrinkage at the gelation point is predicted through a linear extrapolation approach. To demonstrate the effectiveness of the proposed theoretical model, the prediction results are compared against the inline warpage measurement data. One possible cause of the asymmetric/nonaxisymmetric warpage is also addressed. Finally, the influences of some geometric dimensions on the warpage of the molded wafer are identified through parametric analysis.

scholarly journals Preparation of Multicomponent Biocomposites and Characterization of Their Physicochemical and Mechanical Properties

2020 ◽  
Vol 4 (1) ◽  
pp. 18
Author(s):  
Yuriy A. Anisimov ◽  
Duncan E. Cree ◽  
Lee D. Wilson
Keyword(s):  
Mechanical Properties ◽  
Electrical Conductivity ◽  
Physicochemical Properties ◽  
In Situ Polymerization ◽  
Structural Parameters ◽  
Dye Adsorption ◽  
Mechanical Analysis ◽  
Scanning Calorimetry ◽  
Swelling Properties

This work focused on a mutual comparison and characterization of the physicochemical properties of three-component polymer composites. Binary polyaniline–chitosan (PANI–CHT) composites were synthesized by in situ polymerization of PANI onto CHT. Ternary composites were prepared by blending with a third component, polyvinyl alcohol (PVA). Composites with variable PANI:CHT (25:75, 50:50 and 75:25) weight ratios were prepared whilst fixing the composition of PVA. The structure and physicochemical properties of the composites were evaluated using thermal analysis (thermogravimetric analysis (TGA), differential scanning calorimetry (DSC)) and spectroscopic methods (infrared (IR), nuclear magnetic resonance (NMR)). The equilibrium and dynamic adsorption properties of composites were evaluated by solvent swelling in water, water vapour adsorption and dye adsorption isotherms. The electrical conductivity was estimated using current–voltage curves. The mechanical properties of the samples were evaluated using dynamic mechanical analysis (DMA) and correlated with the structural parameters of the composites. The adsorption and swelling properties paralleled the change in the electrical and mechanical properties of the materials. In most cases, samples with higher content of chitosan exhibit higher adsorption and mechanical properties, and lower conductivity. Acid-doped samples showed much higher adsorption, swelling, and electrical conductivity than their undoped analogues.

Synthesis and Characterization of Polyurethane Scaffolds for Biomedical Applications

2009 ◽  
Vol 1243 ◽  
Author(s):  
M.C. Chavarría-Gaytán ◽  
I. Olivas-Armendáriz ◽  
P.E. García-Casillas ◽  
A. Martínez-Villafañe ◽  
C. A. Martínez-Pérez
Keyword(s):  
Biomedical Applications ◽  
Chemical Characterization ◽  
Mechanical Analysis ◽  
Synthesis And Characterization ◽  
Scanning Calorimetry ◽  
Thermally Induced ◽  
Fourier Transformed Infrared Spectroscopy ◽  
Regeneration Of Bone Tissue ◽  
Reflectance Ftir

ABSTRACTPolyurethanes are interesting materials that can be used in biomedical applications for regeneration of bone tissue. In this work the synthesis and characterization of porous polyurethanes to act as scaffold is performed by a thermally induced phase separation technique. The appropriate parameters are determined in order to obtain a porous well interconnected material. Characterization by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) is made in order to determine the thermal stability of the material. Chemical characterization is made by Fourier transformed infrared spectroscopy with attenuated total reflectance (FTIR-ATR). The morphology of the material is observed by a field emission scanning electron microscope (FESEM) and the mechanical properties are measured by dynamic mechanical analysis (DMA).

A detailed characterization of sandalwood-filled high-density polyethylene composites

2020 ◽  
pp. 089270572093915
Author(s):  
Metehan Atagür ◽  
Nusret Kaya ◽  
Tuğçe Uysalman ◽  
Cenk Durmuşkahya ◽  
Mehmet Sarikanat ◽  
...  
Keyword(s):  
High Density Polyethylene ◽  
High Speed ◽  
Loss Modulus ◽  
Weight Fraction ◽  
Mechanical Analysis ◽  
High Density ◽  
Scanning Calorimetry ◽  
Detailed Characterization ◽  
Three Point Bending

In this study, the performance of sandalwood (SW), as an efficient potential filler material for high-density polyethylene (HDPE), was investigated in detail. Firstly, the characterization of SW was conducted by the determination of chemical composition with chemical and thermal analysis methods. The distribution of SW particles, which were used in composite fabrication, was obtained by using a dynamic light scattering analyzer. Then, the composites of SW, whose weight fractions varied from 5% to 20%, with HDPE were produced in a high-speed thermokinetic mixer. The detailed characterization of composites was made by using thermogravimetric analysis, scanning electron microscopy, X-ray diffraction analysis, differential scanning calorimetry, dynamic mechanical analysis (DMA), Fourier transform infrared, thermal conductivity measurements, and tensile and three-point bending tests. From DMA, storage modulus and loss modulus values of the HDPE matrix increased with increasing the weight fraction of SW. It is clearly seen that SW incorporation into HDPE at weight fractions of 5% and 20% exhibited the best improvement in terms of tensile and flexural strengths, respectively. It can be noted that the reinforcement effect of SW for HDPE is more prominent at high temperatures.

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