Polymer composites mechanical property

Key words injectable polymers, composites, mechanical properties, biomaterials. 

Factors Influencing CNT-Polymer Composite Mechanical Properties... 

A surface is that part of an object which is in direct contact with its environment and hence, is most affected by it. The surface properties of solid organic polymers have a strong impact on many, if not most, of their apphcations. The properties and structure of these surfaces are, therefore, of utmost importance. The chemical stmcture and thermodynamic state of polymer surfaces are important factors that determine many of their practical characteristics. Examples of properties affected by polymer surface stmcture include adhesion, wettability, friction, coatability, permeability, dyeabil-ity, gloss, corrosion, surface electrostatic charging, cellular recognition, and biocompatibility. Interfacial characteristics of polymer systems control the domain size and the stability of polymer-polymer dispersions, adhesive strength of laminates and composites, cohesive strength of polymer blends, mechanical properties of adhesive joints, etc. 

Poly(vinyl) alcohol (PVA) is a semi-crystalline polymer, which is already widely used for various applications, either under the form of films or fibers. Compared to other polymers, as it is water-soluble at high temperature, it is easy to process from aqueous solutions. Carbon nanotubes can also be dispersed or solubilized in water via different functionalization approaches. It was quite natural for researchers to try to mix carbon nanotubes and PVA to improve the properties of the neat polymer. In this chapter, we will first examine the different methods that have been used to process CNT/PVA composites. The structures and the particular interaction between the polymer and the nanotube surface have been characterized in several works. Then we will consider the composite mechanical properties, which have been extensively investigated in the literature. Despite the number of publications in the field, we will see that a lot of work is still to be done for achieving the most of the exceptional reinforcement potential of carbon nanotubes. 

Lan and Pinnavaia [6] showed that hybrid organic-inorganic composites exhibited mechanical properties superior to those for their separate composites. Dependence of tensile strength and modulus of epoxy nano-clay composites on the chain length of the clay-intercalated alkylammonium ions is shown in Fig. 28. The presence of the organoclay substantially increased both the tensile strength and modulus relative to the pristine polymer. The mechanical properties increased with any exfoliation in the order ... 

Adhesion at the interface of the polymer-solid is a determining factor for the physical and mechanical properties of polymer composites. Many properties of particulate-filled composites are determined by the adhesion level at the filler-matrix interface. The problems involved in adhesion are very complicated and adhesion cannot be described by any single theory [1]. Many properties of particulate-filled composites are determined by the adhesion level at the filler-matrix interface [2]. However, no theory allows calculation of the adhesion strength of joints from the data on the nature of substrate and polymer or reliable calculation of the energy of the adhesive interaction. The reason for it is the number of factors that influence adhesion [3-9]. 

Lac Each, R., Schone, J., Bierogel, C., Grellmann, W. Instrumented macroindentation techniques for polymers and composites - Mechanical properties, fracture toughness and time - dependent behaviour as a function of the temperature. Macromol. Symp. 315 (2012) 125-131. 

Various tests and analytical methods are used for the characterisation and evaluation of the properties of vegetable oil-based polymer composites. Mechanical tests for properties such as tensile, flexural, compressive, impact, hardness and wear are carried out by a universal testing machine (UTM), and by equipment for testing impact, hardness, abrasion loss, and so on. Weather and chemical resistance tests are performed in UV/ozone, an artificial environmental chamber and in different chemical media. Water uptake and biodegradability tests are carried out by standard ASTM methods. Biodegradability and biocompatibility may be studied by the same procedure as described in Chapter 2. However, in practice only a few such studies have been performed for vegetable oil-based composites. 

In a natural fiber polymer composite, natural fiber is incorporated in a definite volume in the polymer matrix. Mechanical properties can be enhanced by increasing the fiber volume in a composite, but after a certain level, it may start decreasing due to the poor bonding between fiber and matrix. Oksman et al. [9] studied the effect of fiber loading with epoxy polymer. As shown in the Table 22.5, sisal fiber... 

Polypropylene is a very versatile polymer. It has many properties that make it the polymer of choice for various applications (e.g., excellent chemical resistance, good mechanical properties and low cost). There are many ways in which the mechanical properties of polypropylene can be modified to suit a wide variety of end-use applications. Various fillers and reinforcements, such as glass fiber, mica, talc, and calcium carbonate, are typical ingredients that are added to polypropylene resin to attain cost-effective composite mechanical properties. Fibrous materials tend to increase both mechanical and thermal properties, such as tensile strength, flexural strength, flexural modulus, heat deflection temperature, creep resistance, and sometimes impact strength. Fillers, such as talc and calcium carbonate, are often used as extenders to produce a less-costly material. However, some improvement in stiffness and impact can be obtained with these materials. 

Poly(3-hydroxybutyrate) (PHB) 8 was a commercially available, biodegradable, non-linear polyester. Kumagai and Doi established that this polymer (M = 652,000, M /M =l.8) is immiscible with PCL (M =68,000, M /M =1.9) when solvent cast from chloroform [113]. Samples studied by DSC showed two glass-transition temperatures, identical with those of the individual components and invariant with composition. Mechanical properties of the blends were poor and tensile modulus and strength were minimal at 50 wt % of the components. PCL had a complex and accelerating influence on the rate of enzymatic degradation of PHB, the kinetics of which were correlated with scanning electron microscopy observations. 

Zeng, H.L. Gao, C. Wang, Y.P. Watts, P.C.P. Kong, H. Cui, X.W. Yan, D.Y. (2006a). In situ polymerization approach to multiwalled carbon nanotubes-reinforced nylon 1010 composites Mechanical properties and aystaUization behavior. Polymer, 47, 113-122. 

Yarns and fabrics are assemblages of fibers which have commercial application in the textile industry. The fabrics include those formed by weaving and also nonwovens. The geometry of the fabric, as well as the chemical composition of the polymer, influences mechanical properties and applications. The SEM is useful for evaluating (1) construction, (2) coverage, (3) uniformity, (4) surface structure and (5) effects of wear. 

The interface between the filler and the polymer is a complex interface layer. Although the interface layer is very thin (only a few molecules in thickness), it possesses a tremendously complex structure, and the chemical composition, mechanical properties, molecular arrangement, and thermal performance of the interface layer change continuously, as shown in Figure 2.4. 

In almost all cases, GRTP resins have greater chemical resistance than the unreinforced polymer. The mechanical properties of composites far exceed those of the unreinforced polymer. Therefore, even if percent losses in strength were equivalent, the composite would still have a greater strength after exposure. Actually, however, percent strength losses of the composites are generally less than those of the unreinforced polymer. ... 

Aurilia, M., L. Sorrentino, L. Sanguigno, and S. lannace. 2010. Nanofilled polyethersul-fone as matrix for continuous glass fibers composites Mechanical properties and solvent resistance. Advances in Polymer Technology 29 (3) (September 28) 146-160. doi 10.1002/adv.20187. http //doi.wiley.coin/10.1002/adv.20187. 

Novel Syntheses Supramolecular Chemistry Polymer-Ceramic Composites Mechanical Properties and Failure Mechanisms Theory, Modeling, and Simulations Theoretical Modeling Computer Simulations... 

As a further step towards the optimization of the coating process, the influence of the operational variables on the final composite mechanical properties was studied. Four different parameters (polymer powder size, fiber pull speed, and furnace and PCT die temperatures) were independently varied. Then towpregs were produced under preset conditions, and composite plates were obtained by compression molding and subjected to mechanical testing (three-point bending and tensile tests). The overall results are summarized in Table 3. 

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