Composite Systems of Lignocellulosics with Synthetic Polymers

1990 ◽  
Vol 197 ◽  
Author(s):  
Ramani Narayan ◽  
Robert P. Neu

ABSTRACTIncompatible polymer blends are known to have inadequate mechanical properties due to poor adhesion and high interfacial tension between the phases. One such blend that displays this type of behavior is the cellulose acetate-polystyrene blend and is typical of lignocellulosic-synthetic polymer blend systems. Tailor-made cellulose acetate-polystyrene graft copolymers have been synthesized and used as compatibilizers (emulsifiers) to reduce the interfacial tension and improve interfacial mixing. Thermal analyses and morphological studies of the blends with and without the graft copolymer demonstrated that this was indeed the case.

1988 ◽  
Vol 134 ◽  
Author(s):  
Stephen J. Krause

ABSTRACTRigid-rod molecular composites are a new class of high performance structural polymers which have high specific strength and modulus and also high thermal and environmental resistance. A rigid-rod, extended chain polymer component is used to reinforce a matrix of a ductile polymer with the intent of achieving a “composite” on the molecular level. After synthesis, the key to producing a molecular composite is to control morphology to disperse the reinforcing rod molecules as finely as possible in the matrix polymer. Individual rod molecules or bundles of molecular rods must have dimensions which result in a high ratio of length to width (aspect ratio) for efficient reinforcement. To achieve this, the reinforcing rod component must not phase separate at any stage of processing. Morphological characterization techniques, which can measure the orientation and dispersion (or, conversely, the degree of phase separation) of rod molecules provide the tools for correlating theoretically predicted and experimentally observed mechanical properties. Various morphological techniques which have been applied to molecular composite systems will be reviewed, including wide angle x-ray scattering and scanning and transmission electron microscopy. Structure-property correlations for molecular composite systems will be discussed with regard to models for mechanical properties. Application of new morphological techniques will also be discussed.


1993 ◽  
Vol 66 (10) ◽  
pp. 724-730
Author(s):  
Osamu SHIMOMURA ◽  
Yoshio TAKAI ◽  
Masami SAWADA ◽  
Shigetoshi TAKAHASHI ◽  
Kunio GOTO

Author(s):  
Flávio Gomes Fernandes ◽  
Cristiani Viegas Brandão Grisi ◽  
Raunira Costa Araújo ◽  
Diego Alvarenga Botrel ◽  
Solange Sousa

1972 ◽  
Vol 2 (5) ◽  
pp. 464-467
Author(s):  
M. V. Polovnikova ◽  
V. A. Kozyrev ◽  
V. K. Pshedetskaya ◽  
R. I. Khomenko ◽  
I. Z. Zakirov ◽  
...  

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Furkan Ulu ◽  
Ravi Pratap Singh Tomar ◽  
Ram Mohan

Purpose PolyJet technology allows printing complex multi-material composite configurations using Voxel digital designs' capability, thus allowing rapid prototyping of 3D printed structural parts. This paper aims to investigate the processing and mechanical characteristics of composite material configurations formed from soft and hard materials with different distributions and sizes via voxel digital print design. Design/methodology/approach Voxels are extruded representations of pixels and represent different material information similar to each pixel representing colors in digital images. Each geometric region of a digitally designed part represented by a voxel can be printed with a different material. Multi-material composite part configurations were formed and rapidly prototyped using a PolyJet printer Stratasys J750. A design of experiments composite part configuration of a soft material (Tango Plus) within a hard material matrix (Vero Black) was studied. Composite structures with different hard and soft material distributions, but at the same volume fractions of hard and soft materials, were rapidly prototyped via PolyJet printing through developed Voxel digital printing designs. The tensile behavior of these formed composite material configurations was studied. Findings Processing and mechanical behavior characteristics depend on materials in different regions and their distributions. Tensile characterization obtained the fracture energy, tensile strength, modulus and failure strength of different hard-soft composite systems. Mechanical properties and behavior of all different composite material systems are compared. Practical implications Tensile characteristics correlate to digital voxel designs that play a critical role in additive manufacturing, in addition to the formed material composition and distributions. Originality/value Results clearly indicate that multi-material composite systems with various tensile mechanical properties could be created using voxel printing by engineering the design of material distributions, and sizes. The important parameters such as inclusion size and distribution can easily be controlled within all slices via voxel digital designs in PolyJet printing. Therefore, engineers and designers can manipulate entire morphology and material at each voxel level, and different prototype morphologies can be created with the same voxel digital design. In addition, difficulties from AM process with voxel printing for such material designs is addressed, and effective digital solutions were used for successful prototypes. Some of these difficulties are extra support material or printing the part with different dimension than it designed to achieve the final part dimension fidelity. Present work addressed and resolved such issued and provided cyber based software solutions using CAD and voxel discretization. All these increase broad adaptability of PolyJet AM in industry for prototyping and end-use.


Processes ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1073 ◽  
Author(s):  
Goshtasp Cheraghian ◽  
Sara Rostami ◽  
Masoud Afrand

Nanoparticles (NPs) are known as important nanomaterials for a broad range of commercial and research applications owing to their physical characteristics and properties. Currently, the demand for NPs for use in enhanced oil recovery (EOR) is very high. The use of NPs can drastically benefit EOR by changing the wettability of the rock, improving the mobility of the oil drop and decreasing the interfacial tension (IFT) between oil/water. This paper focuses on a review of the application of NPs in the flooding process, the effect of NPs on wettability and the IFT. The study also presents a review of several investigations about the most common NPs, their physical and mechanical properties and benefits in EOR.


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