Effect of chemical interaction between surface oxidized carbon black and carboxylated nitrile rubber on dynamic properties

Monsanto rheometric, dynamic mechanical, and solvent swelling studies indicate that functional groups of oxidized carbon black chemically react with carboxylated nitrile rubber (XNBR) when heated at high temperature for prolonged time. The reinforcing ability of the surface oxidized carbon black, measured by failure and hysteresis properties, is higher than the nonoxidized counterpart. © 1995 John Wiley & Sons, Inc.     

Microstructure and mechanical performance examination of 3D printed acrylonitrile butadiene styrene thermoplastic parts

Fused filament fabrication (FFF) is a process where thermoplastic materials are heated to its melting point and then extruded, layer by layer, to create a three dimensional printed part. Printing occurs in a layered manner, which leads to creation of voids (air gaps) in the 3D printed parts. These voids act as centers for crack initiation, propagation and therefore resulting bulk mechanical properties are lower. This paper focuses on microstructural characterization and analysis of fused filament fabricated tensile test coupons made from acrylonitrile butadiene styrene polymer, at various design conditions. Comparable tensile modulus with injection molded specimens was obtained for FFF design condition that is, slice height (0.1778 mm), raster width (0.4064 mm), raster to raster air gap (−0.0015 mm), contour to raster air gap (−0.0508 mm) and raster angle (0°). Scanning electron microscope studies provided an understanding as to why FFF processed specimens yielded lower failure strain and an insight into the presence of intralayer voids in specimens having lower tensile modulus. The study confirmed that though bulk mechanicals were affected by the combined effect of inter, intra and interfacial voids, intravoids had a predominant influence.     

On the development of uniaxially‐oriented PET tapes for weaving,woven tape fabrics,and their applications

This article reports the development of weavable, uniaxially‐oriented PET tape, and woven‐tape fabric. Fabric from uniaxially‐oriented polypropylene (PP) tape has been commercially produced since the 1960s, and it is the dominant material for flexible industrial packaging, carpet backing, geotextiles and self‐reinforced composites. Attempts had been made over the same period to produce similar poly(ethylene terephthalate) (PET) tape fabric, knowing that it would offer superior performance over PP due to PET's higher stiffness and strength, lower creep, abrasion resistance, and higher temperature capability. However, these attempts could not be translated into industrial production because the PET tapes had a tendency to splinter when subjected to sudden pulls and twists in the weaving loom. This was solved here by blending polymeric additives such as 2% polycarbonate (PC) and 2% linear low‐density polyethylene (LLDPE). Transmission electron microscopy of the oriented tapes showed the 2% PC formed a profusion of nano ellipsoids that adhered well to the PET matrix, and these prevented axial cracks from running through in a brittle manner. The LLDPE formed larger domains with poorer adhesion, but it imparted resistance to splitting from twists and axial folding. The combination of PC and polyolefin imparted a synergistic toughening of the tape. POLYM. ENG. SCI., 59:E120–E132, 2019. © 2018 Society of Plastics Engineers     

Effect of (3-aminopropyl) triethoxysilane on chemorheological behavior of carboxylated nitrile rubber in presence of surface oxidized ISAF carbon black

Carboxylated nitrile rubber and ISAF carbon black chemically interacted when the mix of the two was extruded at high temperature (180°C) in a Monsanto Processibility Tester. Studies on the physical properties of the extrudates and the reaction kinetics of the extrusion process showed that the extent of interaction increased with increase in filler loading, oxygen-containing functional groups on the filler surface, shear rate, extrusion time, and the loading of (3-aminopropyl) triethoxysilane. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 63: 1833–1839, 1997     

Determination of the pressure dependence of polymer melt viscosity using a combination of oscillatory and capillary rheometer

For an accurate simulation of a high-pressure injection molding process by using the CAE software, it is important to understand the pressure sensitivity of a polymer's melt viscosity. The current work describes a method for the determination of the pressure dependence parameter D₃ of the Cross-WLF model. It uses a combined rheological technique using both dynamic and capillary rheometers. Three grades of polycarbonate homopolymers were studied in this work and their complex viscosities were measured using a dynamic shear rheometer. The dynamic data were used to obtain six out of the seven parameters of the Cross-WLF, except D₃. A capillary rheometer fitted with a counter pressure chamber was further used to characterize the pressure dependence of the zero shear viscosity and to determine the D₃ parameter. Finally, the derived parameters were validated by carrying out injection molding with a box tool and comparing the actual pressure profiles with simulation results using the Autodesk® MoldFlow® software. The validation results indicated that actual pressure profiles from the simulation were found to be less than 10% than that of injection molding. POLYM. ENG. SCI., 60:517–523, 2020. © 2019 Society of Plastics Engineers     

3-Aminopropyltriethoxysilane as a promoter in the crosslinking of carboxylated nitrile rubber by surface-oxidized carbon black

The role of aminopropyltriethoxysilane in the interaction between ISAF carbon black and carboxylated nitrile rubber was studied by measurements of bound rubber, physical and dynamic mechanical properties of the vulcanizates, and Monsanto Rheometric studies on the rubber-filler mixes. It is believed that  NH₂ groups of the silane interact with  COOH groups of the rubber, while  OC₂H₅ groups of the silane interact with  OH groups on the filler surface. Weak rubber-filler bonds formed during mixing are converted into a crosslinked structure during high-temperature molding. The extent of crosslinking of the rubber phase by the active sites on the filler surface is greater in the case of oxidized ISAF carbon black, as compared to the nonoxidized grade. © 1996 John Wiley & Sons, Inc.     

Recycling of Poly(phenylene ether) Blends

The effects of postindustry recycling of polymer blends composed of poly(phenylene ether) (PPE) on the properties of the PPE blends were investigated by simulated recycling with multiple molding cycles. Two compositions with different concentrations of PPE were reprocessed with an injection‐molding machine. Mechanical, thermal, rheological, and morphological characterizations were carried out on as‐produced and reprocessed samples to examine the influence of the number of molding cycles on the two specific PPE blends. Efforts were made to determine the effect of each molding cycle on the specific properties of the two PPE blends, including the Elastic (E), modulus, stress at break, strain at break, multiaxial impact, and melt viscosity. The results are discussed in detail. The retention of the properties correlated well with the unperturbed morphology of the compositions before and after recycling, as observed by transmission electron microscopy analyses on fractured tensile samples. However, more in‐depth microanalyses are required to identify the effect of recycling on the individual components present in the studied compositions. In this study, we aimed to establish structure–property relations upon recycling using several characterization techniques. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011