Modifiers and additives

Edenbaum, J., Plastics Additives and Modifiers Handbook, Kluwer, 1992. 

Masda, L. and Xanthos, M A. 1992. Overview of additives and modifiers for polymer blends facts, deductions, and imcertainties. Advances in Polymer Technology 11 237-248. 

Butyl rubber - This material generally had the least endurance in fatigue tests, but it may be adequate for some cardiovascular applications. Advantages include less sensitivity to stress concentrators than Pellethane, a very low permeability to fluids, a moderate creep resistance and widespread availability at low cost. Disadvantages include a relatively low fatigue resistance compared to the elastomers specifically designed for these applications. The rubber tested was not designed for medical applications and had standard rubber additives and modifiers that were cytotoxic unless the material was extracted after manufacture. 

Pascault JP, Galy J, Mechin F (1994) Additives and modifiers for cyanate ester resins. In Hamerton 1 (ed) (1994) Chemistry and technology of cyanate ester resins. Chapman Hall, London, p 112... 

Effects of Additives and Modifiers on the Rheology and Processing of Compounded Systems... 

The effect of additives and modifiers on product properties will not be discussed here because it is beyond the scope of this textbook. We must emphasize, however, that the ultimate objective of compounding additives and modifiers in polymer matrices is to obtain specific multicomponent and multiphase structures and morphologies needed to obtain certain desired product properties. We will only discuss their effects on the compounded systems rheology and, mainly, the shear flow viscosity, and their effects on compounding equipment and processes. 

L. Mascia and M. Xanthos, An Overview of Additives and Modifiers for Polymer Blends Facts, Deductions, and Uncertainties, Adv. Polym. Technol., 11, 237-248 (1992). 

Commercial epoxy adhesives are composed primarily of an epoxy resin and a curing agent. Various additives and modifiers are added to the formulation to provide specific properties. Example trade names and suppliers of these ingredients are included in App. A. The curing agent may be incorporated into the resin to provide a single-component adhesive, or else it may be provided in a separate container to be mixed into the resin immediately prior to application. 

In all these stages the adhesive properties will be determined primarily by the molecular structures of the epoxy resin and curing agent or catalyst employed. Additives and modifiers, of course, will also affect these properties, and they are discussed in later chapters. 

The emulsification process is simple but must be carefully controlled. Epoxy resin is loaded into a high-speed disperser, and the surfactant is added. A defoamer is generally added to prevent excessive aeration, and high-shear mixing is employed. Water is then slowly added to the mixture. The system at this stage has the epoxy resin as the continuous phase and the water as the dispersed phase. As the water addition continues, the ratio of the dispersed phase to the continuous phase increases until a phase inversion occurs. The inversion occurs at about 65 percent volume ratio of dispersed to continuous phase and is accompanied by a rapid reduction in viscosity. Water addition is then continued until the desired solids concentration is achieved. Additional additives and modifiers can be incorporated into the formulation at this stage. 

The applications and performance characteristics of waterborne epoxy adhesives can be significantly improved by the incorporation of additives and modifiers into the adhesive formulation. Fillers such as calcium carbonate, talc, and silicas are often used to adjust the viscosity of the liquid adhesive and the thermal expansion, modulus, and strength characteristics of the cured adhesive film. 

Additives and Modifiers Commonly Used in High-Temperature Adhesives... 

Incorporation of fillers, additives, and modifiers via proper mixing equipment... 

Important factors regarding incoming adherends are the chemical and physical properties of the material. This can be especially important with adhesive bonding because different metal alloys have different surface oxidation, and different elastomers and plastics can have different additives and modifiers. With elastomeric and plastic substrates, lot-to-lot differences should be tested. Often a supplier will change formulations but still be within the requirements of the specification. The difference in formulation may have a profound effect on the quality of the ultimate adhesive bond. 

TRADE NAMES AND MANUFACTURERS EPOXY ADHESIVES, EPOXY RESINS, CURING AGENTS AND CATALYSTS, ADDITIVES AND MODIFIERS... 

Increasing reactivity in the Pauson-Khand reaction. The PK reaction originally suffered from a lack of substrate scope and low reaction yields which prevented it from being widely employed. The discovery of new reaction conditions (additives and modified methods) led to an improvement in yields and reaction times, allowing the scope of the reaction to be expanded. 

Kobayashi T, Killough L (1997) AddCon Asia 97, Int Plastics Additives and Modifiers Conf, Singapore... 

The procedure is based on the group contribution equation of state by M. S. High and R. P. Danner, "A Group Contribution Equation of State for Polymer Solutions," Fluid Phase Equilibria, 53, 323 (1989) and M. S. High Prediction of Polymer-Solvent Equilibria with a Group Contribution Lattice-Fluid Equation of State, Ph.D. Thesis, The Pennsylvania State University, University Park, PA, 1990. Additional and modified group values are from V. S. Parekh Correlation and Prediction of the PVT Behavior of Pure Polymer Liquids, M.S. Thesis, The Pennsylvania State University, University Park, PA, 1991. 

However, they are basically brittle materials, and many types of additives and modifiers have been developed to improve some of their properties. While working to develop special-purpose phenolic materials, the authors found that the compounds being produced had excellent vibration-damping properties (high loss tangent values), and that these properties were preserved to higher temperatures than elastomers generally used for the... 

For a very nice review on 3D cyanide-based magnets see Miller, J. S. MRS Bull, 2000,11, 60. Howell, B. A. Presented in part at the 15th International Conference on Advances in Additives and Modifiers for Polymers and Blends, Las Vegas, NV, February, 2006. 

Staff Written, "Additives and Modifiers— Antistatic Agents," Plastics Compounding 1991192 Redbook, 14(4) 24-26 (July/August 1991). 

---