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Toughening Agent (toughening + agent)

Distribution by Scientific Domains

Polymers and Materials Science	80%

Selected Abstracts

Preparation and characterization of epoxidate poly(1,2-butadiene),toughened diglycidyl ether bisphenol-A epoxy composites

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2009
Jie He
Abstract By the oxidation of liquid poly(1,2-butadiene) (LPB) with H2O2/HCOOH, epoxidate poly(1,2-butadiene) (ELPB) was obtained as a toughening agent to prepare diglycidyl ether bisphenol-A (DGEBA) epoxy composites by using V115 polyamide(PA) as a cross-linking agent. DGEBA, ELPB, and the composites were effectively cured by PA at 100°C for 2 h followed by postcuring at 170°C for 1 h. Thermal gravimetric analysis results in air and nitrogen atmosphere showed that the thermal stability of composites could be improved by the addition of ELPB. Compared with DGEBA/PA, the composites exhibited a decrease in strength at yield but an increase in strain at break with the increase in ELPB amount. The composite with 10% ELPB exhibited both thermal stability and tenacity superior to those of DGEBA/PA and composites with 5 and 20% ELPB, respectively. The improvements in thermal and mechanical properties of composites depended on the formation of Inter Penetrating Networks (IPN) among DGEBA/PA/ELPB and their distributions in the matrix. At an appropriate ELPB amount, the IPN, mostly made of DGEBA/PA/ELPB, may be distributed more evenly in the matrix; less ELPB resulted in the formation of IPN mainly made of DGEBA/PA; excessive addition of ELPB resulted in the local aggregation of ELPB/PA and phase separations. The toughening mechanism was changed from chemically forming IPN made of DGEBA/PA/ELPB to physically reinforcing DGEBA/PA by ELPB/PA with the increase in ELPB addition. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source]

Lignin in jute fabric,polypropylene composites

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 3 2009
B. A. Acha
Abstract In this work, the feasibility of using lignin as a compatibilizer for composites made from jute fiber fabric and polypropylene (PP) was studied. Since lignin contains polar (hydroxyl) groups and nonpolar hydrocarbon, it was expected to be able to improve the compatibility between the two components of the composite. It was found that lignin acted as , nucleation, fire retardant, and toughening agent for PP matrix. Jute composites exhibit higher stiffness, tensile strength, and impact behavior in respect to those of neat PP. Although scanning electron micrographic observations indicate that PP-jute adhesion was slightly improved by lignin addition, additional benefits were only obtained from impact behavior. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source]

Amine functional chloroaniline acetaldehyde condensate-modified epoxy networks

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2008
T. Maity
Abstract An investigation was carried out to modify the fracture toughness of cured diglycidyl ether of bisphenol-A (DGEBA) resin networks with amine functional chloroaniline acetaldehyde condensate (AFCAC) as toughening agent. The resulting networks displayed significantly improved fracture toughness. The AFCAC was synthesized by the condensation reaction of chloroaniline and acetaldehyde in the acid medium (pH-4) and characterized by FTIR and NMR spectroscopy, elemental analysis, viscosity measurements, and mole of primary and secondary amine analysis. The DGEBA and AFCAC were molecularly miscible but developed a two-phase microstructure upon network formation. Epoxy/AFCAC compositions were systematically varied to study the effect of concentration on the impact, adhesive, tensile, and flexural properties of modified networks. The dynamic mechanical analysis and scanning electron microscopy studies showed two-phase morphology in the cured networks where AFCAC particles were dispersed. The AFCAC-modified epoxy network was thermally stable up to around 338°C. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source]

Fracture toughness of modified dental resin systems

JOURNAL OF ORAL REHABILITATION, Issue 8 2003
R. E. Kerby
summary This study compared the relative fracture toughness of a Bis-GMA//TEGDMA (50:50 wt%)-based resin system modified by 5, 10, and 15 wt% of a methacrylate-terminated poly(butadiene-acrylonitrile-acrylic acid) terpolymer toughening agent. After storage in distilled water at 37 ± 2 °C for 7 days, plane strain fracture toughness (KIC) was determined on an Instron testing machine at a 0·5-mm min,1 displacement rate. The glass transition temperature (Tg) in °C was determined after 7 days (dry and wet) storage by thermomechanical analysis. The results of this study showed significantly improved fracture toughness and lowered water sorption with the modified resin systems which was indicated by higher wet glass transition temperatures. [source]

Thermal and mechanical characterization of epoxy resins toughened using preformed particles

POLYMER INTERNATIONAL, Issue 8 2001
J Day
Abstract Preformed, multilayer particles have been used to toughen an epoxy resin. The particles were formed by emulsion polymerization and consist of alternate glassy and rubbery layers, the outer layer having glycidyl groups to give the possibility of chemical bonding of the particles in the cured resin. Two variants of this type of particle were used, termed GM(47/15) and GM(47/37); both types have an overall diameter of 0.5,µm, but the former have a thicker rubbery layer. For comparison, acrylic toughening particles (ATP) with no surface functionality and a liquid carboxyl-terminated butadiene,acrylonitrile (CTBN) rubber were used as toughening agents. The epoxy resin system consisted of a commercial diglycidyl ether of bisphenol A (Shell Epon 828) with diamino-3,5-diethyl toluene as hardener, two commercial sources of which were used, namely Ethacure-100 (Albemarle SA) and DX6509 (Shell Chemicals). These hardeners contain a mixture of two isomers, namely 2,6-diamino-3,5-diethyltoluene and 2,4-diamino-3,5-diethyltoluene Thermogravimetry in nitrogen shows that the preformed toughening particles begin to degrade at 230,°C, whereas the cured resin begins to degrade rapidly at 350,°C. Thus, even though the particles are less thermally stable than the cured resin, their degradation temperature is well above the glass transition temperature of the resin, and their use does not affect the thermal stability of the toughened materials at normal use temperatures. The performance of the toughening agents was compared using Ethacure-100 as the hardener. The GM(47/15) and GM(47/37) toughening particles gave rise to a greater toughening effect than the ATP and the CTBN. For example, the fracture energies were: 0.26,kJ,m,2 for the unmodified resin; 0.60,kJ,m,2 for the resin toughened with CTBN; and 0.69,kJ,m,2 for the resin toughened with the GM(47/15) particles. The ultimate tensile stress of the unmodified epoxy resin was 43,MPa, which increased to 55,MPa when 20,wt% of GM(47/15) toughening particles were added. The toughness of resins cured with the DX6509 hardener were superior to those obtained with the Ethacure-100 hardener, most probably due to DX6509 producing a less-highly-crosslinked network. This highlights the sensitivity of the toughening process to the hardener used, even for hardeners of a similar nature. © 2001 Society of Chemical Industry [source]