Effects of Material Parameters

Of the material parameters shown in Table 8.3, the molecular weight, copolymerization, 

Monomer type Polyester Method Temperature range (°C) A h k (min 

Polymer blending is commercially advantageous to prepare PLA-based materials with a wide variety of physical and hydrolytic degradation properties. There are five primary factors 

By varying the material parameters, the hydrolytic degradation mechanism, behavior, and rate can be controlled. In other words, these parameters are carefully manipulated when PLA-based materials are biomedically and environmentally applied by using the hydrolyzability function. In the following section, the hydrolytic degradation conditions are temperature of 37°C and pH of about 7, unless otherwise specified. 

FIGURE 21.13 Mn change of amorphous PLLA having high and low molecular weights (PLLA(H) and PLLA(L), respectively), P(LLA-co-DLA) (77/23), poly(L-lactide-co-glycolide) (P(LLA-C( -GA)) (81/19), and poly(L-lactide-co-8-caprolactone) (P(LLA-co-CL)) (82/18) with respect to hydrolytic degradation in a phosphate-buffered solution [39, 40, 159]. 

Copolymerization Of the lactone comonomers, the GA and CL units are frequently utilized to elevate the hydrolytic degradation rate and elongation at break, and to lower Young s modulus of PLA-based polymers. For hydrolytic degradation of P(LA-co-GA), Vert and coworkers and other research groups [6, 270, 296, 297] intensively investigated and obtained information that is summarized in several review articles. With respect to the 

Li and Kissel [195] prepared linear and 4-arm/8-arm branched block copolymers of LLA and GA coinitiated with branched PEO and showed that the branching affected the NHD as traced by weight loss and molecular weight change. 

On the other hand, Joziasse et al. [243] investigated the NHD of linear and branched P(LLA-C6 -DLA-C6 -GA)/Iinear poly (TMC-C6 -CL) blends and found that the blends of branched copolymers retained their mechanical properties for longer periods than did the linear copolymers. 

---

Crowson, R.J. and Folkes, M.J. (1980) Rheology of short glass fiber-reinforced thermoplastics and its application to injection molding. II. The effect of material parameters. Pdym. Eng. Sd.. 20 (14), 934-940. 

Analytic chapters provide fundamentals to synthetic chapters. Chapter 3 evaluates and examines the model proposed in chapter 2. In chapter 4, it is studied that the effects of material parameters to design and control variables for chapter 5 and 6. In chapter 7, methods to reach desired position and to derive objective shapes are proposed, which are integrated in chapter 8. The structure of this book is illustrated in Figure 1.2. 

Cox, M. K. (1992) The effect of material parameters on the properties and biodegradation of BIOPOL , in Biodegradable Polymers and Plastics, (eds M. Vert et al.). Royal Society of Chemistry, Cambridge pp. 95-100. 

The application of a selective pyrolysis process to the recovery of chemicals from waste PU foam is described. The reaction conditions are controlled so that target products can be collected directly from the waste stream in high yields. Molecular beam mass spectrometry is used in small-scale experiments to analyse the reaction products in real time, enabling the effects of process parameters such as temperature, catalysts and co-reagents to be quickly screened. Fixed bed and fluidised bed reactors are used to provide products for conventional chemical analysis to determine material balances and to test the concept under larger scale conditions. Results are presented for the recycling of PU foams from vehicle seats and refrigerators. 12 refs. 

The angular momentum conservation equation couples the viscous and the elastic effects. The angular profiles of the director and the effective viscosity data are computed for one set of material parameters based on published data in literature. The velocity profiles are also attained from the same dataset. The results show that the alignment of molecules has a strong influence on the lubrication properties. 

Luft and Tsuo have presented a qualitative summary of the effects of various plasma parameters on the properties of the deposited a-Si H [6]. These generalized trends are very useful in designing deposition systems. It should be borne in mind, however, that for each individual deposition system the optimum conditions for obtaining device quality material have to be determined by empirical fine tuning. The most important external controls that are available for tuning the deposition processs are the power (or power density), the total pressure, the gas flow(s), and the substrate temperature. In the following the effects of each parameter on material properties will be discussed. 

In many atomization processes, physical phenomena involved have not yet been understood to such an extent that mean droplet size could be expressed with equations derived directly from first principles, although some attempts have been made to predict droplet size and velocity distributions in sprays through maximum entropy principle.I252 432] Therefore, the correlations proposed by numerous studies on droplet size distributions are mainly empirical in nature. However, the empirical correlations prove to be a practical way to determine droplet sizes from process parameters and relevant physical properties of liquid and gas involved. In addition, these previous studies have provided insightful information about the effects of process parameters and material properties on droplet sizes. 

In the following sections, the correlations for droplet sizes generated by different types of atomizers will be summarized, and the effects of process parameters and material properties on droplet sizes will be discussed on the basis of the analytical and experimental studies available in published literature. 

Danilova-Volkovskaya G.M. The effect of processing parameters and modifiers on the properties of polypropylene and PP-based composite materials. — Doctoral Thesis, (technical sciences). 2005, p. 273. 

Muruganandham, M Swaminathan M. Ti02-UV photoeatalytie oxidation of Reactive Yellow 14 Effect of operational parameters. Journal of Hazardous Materials, 2006 in press. 

Ebert, W. L. Mazer, J. J. 1994. Laboratory testing of waste glass aqueous corrosion effects of experimental parameters. In Barkatt, A. Van Konynenbourg, R. A. (eds) Scientific Basis for Nuclear Waste Management XVII. Materials Research Society Symposia Proceedings, 333,27-40. 

Again we refer to the review by Tallec [36] where the effect of system parameters on enantioselectivity is summarized. For a given substrate, the most important factors are electrode material, electrode pretreatments, modifier structure, solvent, electrolyte, pH and buffer system, voltage and temperature. 

---