Curing of Low Shrinkage Unsaturated Polyester resins in     Reactive Processing
{'Code': '07020000', 'Directorate': {'LongName': 'Directorate For Engineering'}, 'Division': {'LongName': 'Div Of Chem, Bioeng, Env, & Transp Sys'}}
{'SignBlockName': 'Maria Burka'}
Unsaturated polyester resins are widely used thermosets in polymeric            composites because they offer a good balance of properties, are                 relatively inexpensive, and are amenable to most fabrication                    processes.  With the aid of fillers, reinforcements and additives,              they are usually available in the form of compounds for:  (1)                   compression molding (sheet molding compound, SMC), (2) injection                molding (bulk molding compound, BMC), (3) resin transfer molding                (RTM), and (4) pultrusion.  Their uses are in the automotive, housing,          marine, and electric/electronics industries (for example, SMC is                widely used for auto body exteriors).  Unsaturated polyester resins             are a mixture of saturated and unsaturated dicarboxylic acids with              glycols.  Due to high polymerization shrinkage during cure, structural          and surface flaws results because as the polyester crosslinks with              styrene it shrinks away from the mold walls. Many physical changes              occur during polymerization including:  (1) microgel formation at a             very early stage of polymerization due to the high extent of                    intramolecular reaction; (2) macro-scale gelation where materials               change from a viscous fluid to a network gel with chemical                      crosslinking; and (3) glass transition (i.e., vitrification) where the          reacting mixture changes from a rubbery material to a glassy polymer            at a later stage of polymerization.  These changes occur during the             course of reaction and may affect the ongoing chemical reaction.                Additional problems with the process are due to the fact that the               reaction has to approach complete conversion because the residual               reactants can not be removed and may be defects in the molded product,          and, in order to compete with thermoplastic manufacturing, reaction             rate has to be very high to reduce the cycle time (on the order of              seconds or minutes).                                                                                                                                            The goal of this research are to increase understanding of the                  reaction mechanisms and molecular structure of unsaturated polyester            resins, specifically (i) to understand the mechanism of microgel                formation and macro-crosslinking in the chain growth                            crosslinking copolymerization of unsaturated polyester resins,                  (ii) to understand the effect of processing conditions, molecular               structure of resins, type and concentration of initiator, and low               profile additives on the reactions kinetics and morphological                   changes of low shrinkage unsaturated polyester resins, (iii) to                 propose a mechanistic curing model based on the true reaction                   mechanism of unsaturated polyester resins (i.e., an inhomogeneous               chain growth crosslinking copolymerization), which can be used                  for the design of new materials and the optimization of                         processing methods, and (iv) to establish the interrelationship                 between the above mentioned results, cure time and surface finish               of molded parts.  Information resulting from this research will                 be used for solving the problems of poor surface quality of                     molded parts and too long a cycle time.  This is an                             Industry/University Cooperative Research (IUCR) effort.                         Scientists from three companies will participate in the research                program.  The companies will also contribute materials and the                  use of some of their facilities.
{'FirstName': 'Ly James', 'LastName': 'Lee', 'EmailAddress': 'leelj@chbmeng.ohio-state.edu', 'StartDate': '03/01/1989', 'EndDate': None, 'RoleCode': 'Principal Investigator'}
{'Name': 'Ohio State University Research Foundation -DO NOT USE', 'CityName': 'Columbus', 'ZipCode': '432101016', 'PhoneNumber': '6146888734', 'StreetAddress': '1960 KENNY RD', 'CountryName': 'United States', 'StateName': 'Ohio', 'StateCode': 'OH'}
{'Code': '1403', 'Text': 'Proc Sys, Reac Eng & Mol Therm'}
{'url': 'https://www.nsf.gov/awardsearch/download?DownloadFileName=1988&All=true', 'xml': '8820674.xml'}