A great challenge related to polymers research has been the development of reliable models enabling prediction of polymer end-use properties according to the initial operational conditions-either during the polymerization process or the transformation process phases. These models can be utilized to produce final devices with specified properties in a more economic and faster way. The first step for building up such kind of model is the information about the relationship between the intrinsic properties, which is a convenient way to develop the models. The intention is to optimize the operational conditions of transformation systems, resulting in better products with lower costs. Empirical models are suitable workable solutions to represent complex systems in which it is difficult and expensive or too time-consuming to develop a detailed deterministic model. Bearing this in mind, this article aims to build-up empirical models relating intrinsic and end-use properties of polymers, which can be applied in the injection plastic molding. The development was carried out through resins characterizations together with the impact quantification of process operating variables including their interactions. Polyethylene resins produced in a second generation petrochemical industry were used as a case study. The first generation industries include the production of basic products from naphtha, whereas the second generation involves the transformation of basic petrochemicals, such as ethane and propane, into thermoplastic resins, polyethylene, and polypropylene. The developed models were compared to experimental data and good predictions were obtained. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 114: 3780-3792, 2009