This technology simplifies manufacturing processes for plastics while also improving melt flow characteristics of polymers. It is a method for inexpensive...
This technology simplifies manufacturing processes for plastics while also improving melt flow characteristics of polymers. It is a method for inexpensive synthesis of monomers for production of hyperbranched polymers (HBP). These polymers maintain desirable properties of linear polymers, such as thermal and chemical stability, while also maintaining high solubility and low viscosity.
This technology offers the plastics additives industry a way to produce an optimal melt flow product while simplifying and reducing costs of the manufacturing process. It can be used to produce coatings, additives, or stand-alone polymers as well as other materials. It is thermally stable and can conform to any architecture needed.
The technology includes methods for producing AmBn monomers and for producing high molecular weight (MW) star, linear, hyperbranched, and dendritic polyethermides (PEIs) from those monomers and their various combinations. Careful control of the chemistry of the monomers can selectively target production of processible, highly branched (hyperbranched) polymers that are mechanically, thermally, and hydrolytically stable as well as resistant to oxidative degradation.
The process typically takes an aromatic monomer containing silylated phenols and fluorphthalimed reactive groups (ABn) types monomer and reacts it with a catalytic amount of cesium fluoride in high boiling, polar, aprotic solvents to produce a high-MW polymer This technique produces polymers that are highly amorphous and easily isolated from crystalline monomers that are easily synthesized and purified in three steps from inexpensive commercial starting materials.
Further modifications produce a polymer with physical properties that are dominated by the endgroup functionalities and not by the repeat unit. The process controls the degree of branching and the polymer's structure, thereby targeting and controlling physical properties that lie between those of a linear and a "perfect" dendritic structure.
The degree of branching (DB) of a polymer is defined on a scale from 0 to 1, with linear polymers approaching 0 and dendritic (maximally branched) polymers approaching 1. Those in between are termed branched or hyperbranched. This technology can produce polymers exhibiting the entire range of branching.
Physical properties of dendritic macromolecules, such as crystallinity, viscosity and solubility, are determined by their unique globular shape and the endgroups that occupy their periphery. Techniques for producing high MW, "perfect" dendrimers require many synthetic steps that increase the cost and limit the scale of production. This method has few synthetic steps and provides macromolecules with properties very similar to dendrimers with a fraction of the time and cost.
The physical properties of linear polymers are determined by intermolecular interactions and the structure of the repeat itself. Linear polymers increase in viscosity and decrease in solubility as their MW increases. For uses such as coatings or films, this quality makes the processing difficult. This technology can create highly branched, high-MW polymers with characteristics of linear polymers but much lower viscosities and much higher solubilities. This makes it ideal for use as an additive to commercially available polymers for reducing the melt and/or solution viscosity without compromising the physical properties of the parts or composites (e.g., injection molded) being created. Since the materials are high molecular weight, they are ideal candidates as viscosity reducers for coatings to reduce VOC content.
The synthesis of hyperbranched monomers, historically costly and difficult, yields only small quantities of material. Techniques for improving the scaleability of hyperbranched monomers have not produced polymers that can withstand severe chemical, mechanical, thermal, or oxidative conditions. This new technology produces hyperbranched polymers that are amorphous solids with excellent chemical stability: they can withstand temperatures above 500 C in air and nitrogen, their chemical solubility profile can be easily modified, and they can be produced in bulk quantities while still maintaining their preferred characteristics.
Lastly, the technology can effectively eliminate separation of polymer phases within blended products. It can camouflage hyperbranched polymers by selecting endgroups or linear polymer chains that make the particle compatible or homogenous within the matrix.
Researchers from the Beckman institute at the University of Illinois are developing a system for cooling structural materials inspired on nature's transpiration....
Researchers from the Beckman institute at the University of Illinois are developing a system for cooling structural materials inspired on nature's transpiration. Using porous materials and leveraging capillary forces, Scott White's lab created a transpiration system to cool down a surface. The system is autonomous, self powered, and inexpensive. In addition, the principle of transpiration make this cooling solution self regulated requiring minimum user input after the system is installed. The new system will enable the use of polymer materials for applications where high temperatures would degrade non-cooled polymers.