scholarly journals Preparation and Characterization of Waterborne Polyurethaneurea Composed of Dimer Fatty Acid Polyester Polyol

2006 ◽  
Vol 2006 ◽  
pp. 1-10 ◽  
Author(s):  
Lin Jiang ◽  
Qiang Xu ◽  
Chun Pu Hu
Keyword(s):  
Mechanical Properties ◽  
Fatty Acid ◽  
Surface Hydrophobicity ◽  
Glycol Adipate ◽  
Carbonyl Groups ◽  
Polyester Polyol ◽  
Water Contact ◽  
Aqueous Dispersions ◽  
Hard Segments

A series of polyurethaneurea (PUU) aqueous dispersions, which were stable at ambient temperature for more than 1 year, were prepared with C36-dimer-fatty-acid-based polyester polyol, isophorone diisocyanate, dimethylol propionic acid, and ethylenediamine. The particle size of all these PUU (DPU) aqueous dispersions (<100nm) was less than that of comparable specimens, that is, poly-(neopentyl glycol adipate) polyester-polyol-based PUU (APU) aqueous dispersions, and the polydispersity index was very narrow (≤1.13). The films prepared with the DPU aqueous dispersions exhibited excellent waterproof performance, such as low amount of water absorption (1.3 wt%), and good mechanical properties (hardness and tensile strength), resulting from the strong hydrogen bonding in urea carbonyl groups and the perfect ordered structure of hard segments compared with those prepared with the APU aqueous dispersions. The surface hydrophobicity of the films prepared with modified DPU aqueous dispersions, which were modified with a fluorinated polyacrylate emulsion, was excellent, as the water contact angle on the surface of such films rose up to 100. The mechanical properties of such modified DPU films were further enhanced.

scholarly journals Improved Mechanical, Thermal, and Hydrophobic Properties of PLA Modified with Alkoxysilanes by Reactive Extrusion Process

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2475
Author(s):  
Elena Torres ◽  
Aide Gaona ◽  
Nadia García-Bosch ◽  
Miguel Muñoz ◽  
Vicent Fombuena ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Reactive Extrusion ◽  
Surface Hydrophobicity ◽  
Extrusion Process ◽  
Mechanical And Thermal Properties ◽  
Water Contact ◽  
Covalent Bonds ◽  
Melting Temperatures ◽  
Free Process ◽  
Reactive Extrusion Process

An eco-friendly strategy for the modification of polylactic acid (PLA) surface properties, using a solvent-free process, is reported. Reactive extrusion (REX) allowed the formation of new covalent bonds between functional molecules and the PLA polymeric matrix, enhancing its mechanical properties and modifying surface hydrophobicity. To this end, the PLA backbone was modified using two alkoxysilanes, phenyltriethoxysilane and N-octyltriethoxysilane. The reactive extrusion process was carried out under mild conditions, using melting temperatures between 150 and 180 °C, 300 rpm as screw speed, and a feeding rate of 3 kg·h−1. To complete the study, flat tapes of neat and functionalized PLA were obtained through monofilament melt extrusion to quantify the enhancement of mechanical properties and hydrophobicity. The results verified that PLA modified with 3 wt% of N-octyltriethoxysilane improves mechanical and thermal properties, reaching Young’s modulus values of 4.8 GPa, and PLA hydrophobic behavior, with values of water contact angle shifting from 68.6° to 82.2°.

Synthesis and characterization of UV-cured epoxy acrylate resin with cyclic methacrylate as diluents

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yuyue Guo ◽  
Shudong Lin
Keyword(s):  
Mechanical Properties ◽  
Uv Light ◽  
Epoxy Acrylate ◽  
Thermal Stabilities ◽  
Content Type ◽  
Alkyl Groups ◽  
Hard Segments ◽  
Acrylate Resin ◽  
Epoxy Acrylate Resin

Purpose This paper aims to investigate the effects on material performance in the epoxy acrylate resin system owing to the existence of the different ring of the cyclic methacrylate. In this paper, cyclic methacrylate as diluents was added into epoxy acrylate (EA) resin by ultraviolet (UV)-cured polymerization to investigate the effects on material performance owing to the existence of the different rings. Design/methodology/approach EA and 1-adamantyl methacrylate were synthesized by traditional methods according to previous papers, respectively. After adding different cyclic methacrylate as diluents to the EA oligomers, the system was exposed to the UV-light for polymerization. Findings The hydrophobic properties of the cured materials were increased slightly because of the alkyl groups from the methacrylate. The thermal stabilities and mechanical properties of the resins were enhanced by the cyclic diluents with the hard segments. Meanwhile, the crosslink density of the polymer decreased with the bulky group like adamantly owing to its huge structure. Research limitations/implications The cyclic methacrylates were introduced into EA oligomers for decreasing the viscosity and increasing the materials performances, which could be recognized as new diluents applied in UV-cued polymerization. Originality/value The results of this study will be conducive to fabricate EA resins possessed with high thermal stabilities and mechanical properties by convenient UV-cured polymerization.

Production and characterization of chitosan and glycerol-chitosan films

MRS Advances ◽  
2018 ◽  
Vol 3 (61) ◽  
pp. 3601-3610 ◽  
Author(s):  
María E. Castelló ◽  
Pablo S. Anbinder ◽  
Javier I. Amalvy ◽  
Pablo J. Peruzzo
Keyword(s):  
Mechanical Properties ◽  
Contact Angle ◽  
Visible Spectroscopy ◽  
Reaction Conditions ◽  
Water Contact ◽  
Plasticizer Content ◽  
Flexible Films ◽  
Subsequent Conversion ◽  
Uv Visible

This work presents the study of the isolation of chitin from residues of the Patagonian shrimp (Pleoticus muelleri), and its subsequent conversion to chitosan under different reaction conditions. The obtained products were characterized by evaluating their molecular weight (Mw) and degree of deacetylation (DD). In addition, chitosan- glycerol films were prepared (5, 10 and 20% w/w of plasticizer content), using a neutralization process during the unmolding step. The films were characterized by infrared (FTIR) and UV-Visible spectroscopy and scanning electron microscopy (SEM). In addition, its behavior against water (contact angle and water sorption) and mechanical properties were also studied. It was observed that 72 hours of reaction time at 120 °C were necessary to obtain a chitosan sample with the desirable solubility properties from the chitin extracted from Pleoticus muelleri shells. The chitosan-glycerol films turned out to be systems of high transparency and their properties depended on the plasticizer content, obtaining homogeneous systems for concentrations up to 10% w/w. In addition, the films were found to be more hydrophilic than the reference material, with smaller contact angle and greater water absorption values, obtaining more flexible films in view of their mechanical properties.

Technical possibilities for recycling plastics from agribusiness

2021 ◽  
pp. 147776062110194
Author(s):  
Francisco Cadena ◽  
María Belén Aldás ◽  
Alex Darío Aguilar ◽  
Allyson Inga ◽  
Daniel Cando
Keyword(s):  
Mechanical Properties ◽  
Industrial Sector ◽  
Plastic Waste ◽  
Carbonyl Groups ◽  
Banana Production ◽  
Washing Process ◽  
Protective Element ◽  
Useful Life ◽  
Two Stages

Plastic waste generated by the Ecuadorian agro-industrial sector represents one of the main environmental impacts, particularly in floricultural and banana production, as a result of its use as a greenhouse cover and as a protective element for the fruit cluster, respectively. The situation become more complicated because of the level of degradation caused by environmental exposure and the degree of contamination due to the use of agrochemicals that plastics present once their useful life has expired. The current research was divided into two stages: characterization of plastic waste and conditioning prior to reprocessing. The results revealed the plastic waste of the floricultural and banana sector, whose predominant material corresponds to LDPE and HDPE, respectively, presents a level of contamination that allows them to be considered as “non-hazardous” waste, which allows them to be recycled, but their processes must be properly controlled and carried out by qualified people. The level of degradation in the exposed banana bags showed losses of mechanical properties of tensile less than 50%, which means that the material is not degraded and it is feasible to recycle it directly. Additionally, the FTIR-ATR spectra on both sides of the film in the samples did not register representative bands of oxidation. On the other hand, in the greenhouse waste, the losses of mechanical properties of tensile strength above 50% as well as the noticeable formation of carbonyl groups in the structure of the material showed the degradation of the plastic. Therefore, the feasibility of recycling will depend on the incorporation of virgin material. The conditioning of the waste for subsequent recycling revealed the need of a washing process consisting of four stages: initial cleaning, pre-wash, washing, and air-drying.

Microstructural and fractographic characterization of B4C-Al cermets tested under dynamic and static loading

1989 ◽  
Vol 47 ◽  
pp. 562-563
Author(s):  
Gyeung Ho Kim ◽  
Mehmet Sarikaya ◽  
D. L. Milius ◽  
I. A. Aksay
Keyword(s):  
Thin Film ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
Static Loading ◽  
Carbon Deposition ◽  
Full Density ◽  
Unique Combination ◽  
Strong Component ◽  
Reaction Products

Cermets are designed to optimize the mechanical properties of ceramics (hard and strong component) and metals (ductile and tough component) into one system. However, the processing of such systems is a problem in obtaining fully dense composite without deleterious reaction products. In the lightweight (2.65 g/cc) B4C-Al cermet, many of the processing problems have been circumvented. It is now possible to process fully dense B4C-Al cermet with tailored microstructures and achieve unique combination of mechanical properties (fracture strength of over 600 MPa and fracture toughness of 12 MPa-m1/2). In this paper, microstructure and fractography of B4C-Al cermets, tested under dynamic and static loading conditions, are described.The cermet is prepared by infiltration of Al at 1150°C into partially sintered B4C compact under vacuum to full density. Fracture surface replicas were prepared by using cellulose acetate and thin-film carbon deposition. Samples were observed with a Philips 3000 at 100 kV.

Characterization of interfaces in CVD-coated nicalon fiber-reinforced SiC

1989 ◽  
Vol 47 ◽  
pp. 556-557
Author(s):  
K.L. More ◽  
R.A. Lowden
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Chemical Vapor ◽  
Chemical Vapor Infiltration ◽  
Frictional Stress ◽  
Fiber Reinforced ◽  
Pull Out ◽  
Carbon Coated ◽  
Fiber Matrix

The mechanical properties of fiber-reinforced composites are directly related to the nature of the fiber-matrix bond. Fracture toughness is improved when debonding, crack deflection, and fiber pull-out occur which in turn depend on a weak interfacial bond. The interfacial characteristics of fiber-reinforced ceramics can be altered by applying thin coatings to the fibers prior to composite fabrication. In a previous study, Lowden and co-workers coated Nicalon fibers (Nippon Carbon Company) with silicon and carbon prior to chemical vapor infiltration with SiC and determined the influence of interfacial frictional stress on fracture phenomena. They found that the silicon-coated Nicalon fiber-reinforced SiC had low flexure strengths and brittle fracture whereas the composites containing carbon coated fibers exhibited improved strength and fracture toughness. In this study, coatings of boron or BN were applied to Nicalon fibers via chemical vapor deposition (CVD) and the fibers were subsequently incorporated in a SiC matrix. The fiber-matrix interfaces were characterized using transmission and scanning electron microscopy (TEM and SEM). Mechanical properties were determined and compared to those obtained for uncoated Nicalon fiber-reinforced SiC.

PREPARATION AND CHARACTERIZATION OF REPROCESSED COMPOSITES OF POLYPROPYLENE REINFORCED BY WOOD FIBERS: PHYSICAL AND MECHANICAL PROPERTIES

2017 ◽  
Author(s):  
Thais Helena Sydenstricker Flores-Sahagun ◽  
Kelly Priscila Agapito ◽  
ROSA MARIA JIMENEZ AMEZCUA ◽  
Felipe Jedyn
Keyword(s):  
Mechanical Properties ◽  
Physical And Mechanical Properties ◽  
Wood Fibers

Emerging Techniques for the Characterization of Nano-Mechanical Properties of Integrated Circuit Components

2008 ◽  
Author(s):  
Nicholas Randall ◽  
Rahul Premachandran Nair
Keyword(s):  
Mechanical Properties ◽  
Quality Control ◽  
Integrated Circuits ◽  
Integrated Circuit ◽  
Manufacturing Process ◽  
Solder Bumps ◽  
Initial Work ◽  
Circuit Components ◽  
Materials Used

Abstract With the growing complexity of integrated circuits (IC) comes the issue of quality control during the manufacturing process. In order to avoid late realization of design flaws which could be very expensive, the characterization of the mechanical properties of the IC components needs to be carried out in a more efficient and standardized manner. The effects of changes in the manufacturing process and materials used on the functioning and reliability of the final device also need to be addressed. Initial work on accurately determining several key mechanical properties of bonding pads, solder bumps and coatings using a combination of different methods and equipment has been summarized.

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