Nature: front end polymerization can significantly reduce the energy required for polymerization, and can be applied to 3D printing

Now, researchers have found a new way to manufacture important industrial polymer materials, such as thermosetting polymer and fiber-reinforced polymer composites, at a lower cost than before This method can be used to manufacture composite sheet products such as aircraft fuselage, and reduce the energy needed to 10 orders of magnitude lower than the current industrial manufacturing technology Compared with the conventional methods, the obtained polymers and composites have the same mechanical strength, thermal stability, bending resistance and chemical resistance To manufacture high-performance thermosetting parts, it is necessary to use autoclave to heat them under high pressure for curing Before that, it is necessary to pre cure the monomer resin The size of autoclave will limit the size of production parts, the larger the parts, the larger the autoclave is needed And for large components, the process is very slow and requires a lot of energy Jeffrey S Moore and Scott R white from the University of Illinois at Urbana Champaign led a research team to develop this new polymer processing and molding method (nature, DOI: 10.1038 / s41586-018-0054-x) Researchers estimate that the traditional curing of a small part of the 787's fuselage requires about 96000 kilowatt hours of power, enough for nine urban residents to use in a year The researchers believe their new polymer curing method can reduce the power required to produce the same parts to 9.6 milliwatt hours, which is only enough for 25 watt incandescent lamps to last for 2 seconds 3D printing spiral structure model and monomer molecular model (source: C&EN) the new method studied by the team, the first step is to preform the solution (or gel) containing the mixture of Dicyclopentadiene (DCPD) monomer or DCPD fiber They then use heat sources to initiate polymerization of preformed materials Once the initiation polymerization starts, the monomer has enough internal energy to polymerize itself into thermosetting products without the assistance of autoclave or other devices This process is called front-end polymerization because the polymerization is rapid along the front-end The front-end polymerization of DCPD can produce high-performance crosslinked thermosetting poly (dicyclopentadiene) (PDCPD) polymers and composites The specific reaction used by the researchers was ruthenium catalyzed front-end ring opening metathesis polymerization (fromp) Frump has been studied by other scientists before, but it is difficult to use because of its short curing time For example, unheated DCPD monomer resin or fiber mixtures are essentially cured within 30 minutes In most cases, the curing process is too fast for the raw material to be preformed before initiating polymerization The team's key research achievement is the recently discovered alkyl phosphite inhibitor The processing time of DCPD monomer can be extended from 30 minutes to 30 hours by adding this inhibitor In this way, fromp can be used to construct a series of complex structures of PDCPD polymers or composites An example of fromp where n is the degree of polymerization and M is the degree of crosslinking (source: C & EN) researchers used 3D printers to build spiral structure models and DCPD molecular models They also made fiber-reinforced composite boards, which have similar performance to similar products in industrial production and can meet the requirements of high-performance applications In the process of curing, only the heat is needed when initiating Once initiating, no heat source is needed to supply energy, so the energy consumption of this method is much less than that of traditional curing And the curing process is also faster, without the need for additional high-pressure heating equipment White and his colleagues hope to use the technology to develop new ways to make complex structures They have filed several patent applications related to the research, but have not yet commercialized them.