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Cheaper Carbon Fiber Composites

U.S. Patent 9,365,685 (June 14, 2016), “Method of Improving Adhesion of Carbon Fibers with a Polymeric Matrix,” Frederic Vautard, Soydan Ozcan and Felix Leonard Paulauskas (UT-Battelle LLC, Oak Ridge, Tenn., USA). 

Epoxy carbon-fiber-reinforced composites are known for their outstanding mechanical properties and low density. However, they are expensive and difficult to process, making broader application to consumer markets too expensive. Furthermore, the mechanical properties of cheaper resins do not match that of high-performance epoxy resins. Vautard, Ozcan and Paulauskas functionalized carbon fibers with partially cured epoxy or amine-sizing agents. Epoxy-reactive groups include hydroxyl (OH), carboxyl (COOH) and amino (NH₂) groups. These fibers can be used in vinyl polymers as well as condensation polymers with good results. Amine groups can covalently bond with a variety of polymers, including polycarbonates, polyesters, acrylics, nylons, polyether ether ketones, polysulfones, polyvinylalcohol and polyimides.  

Breathable Film for Cheese Packaging

U.S. Patent 9,365,687 (June 14, 2016), “PVDC Formulation and Heat-Shrinkable Film,” Dimitris Gkinosatis (Flexopack S.A. Plastics Industry, Koropi, Greece).  

Special foods such as gassing cheese products require special packaging that release carbon dioxide gas that causes package ballooning. At the same time, oxygen permeability must be low enough to prevent oxidation. The majority of heat-shrinkable film uses polyvinylidene chloride (PVDC) resins to stop oxygen diffusion, which also prevents carbon dioxide diffusion. Gkinosatis developed a special polymer blend consisting of a PVDC copolymer, ethylene vinyl acetate copolymer, polyvinyl chloride (PVC), epoxidized oil and other additives. Their material contains less than 2 wt% ethylene vinyl acetate copolymer with 40 to 50 wt% vinyl acetate per weight of PVC content, 0 to 2 wt% silica, talc and other materials such as silicones, high-density polyethylene or tetrasodium pyrophospthate. In addition, multilayer film is developed with a PVDC layer. The other layers may contain ethylene alpha olefin copolymers, propylene alpha olefin copolymers, propylene ethylene copolymers, styrene polymers or ionomers. These materials do prevent long-term ballooning for packaged gassing cheeses while preventing oxygen diffusion.

Portable Pyrolysis

U.S. Patent 9,365,775 (June 14, 2016), “Waste Recycling System,” Gaylen La Crosse, Jeremy La Crosse and Michael Galich (YAGS LLC, Evanston, Ill., USA).

These days, the volume of plastics discarded by consumers is enormous, leading to ever-growing landfills. Recycling is becoming more popular but separation, selection and transportation continues to be a challenge. Pyrolysis is promising but catalysts are expensive and transportation is, still, a problem. La Crosse, La Crosse and Galich developed a portable reactor system for pyrolysis that can easily be scaled up or down and is operated without a catalyst. This system consists of two reactor sections connected to a condenser. The waste is heated at pressures less than atmospheric pressure to 500 to 800˚ C to convert the waste hydrocarbons to gaseous hydrocarbons. The product is transferred to condensers forming liquids. Char is removed in the second reactor. Candidate industries include paper mills, waste rubber tires, and animal and agricultural wastes.

Rotomolding Large Structures 

U.S. Patent 9,370,882 (June 21, 2016), “Cost-Effective and Efficient Air Circulation System for a Vehicle having Rotomolded Body Assembly,” Nigel Giddons and John William Taylor (Tata Technologies Pte. Ltd., Singapore).

Effective vehicle air circulation and ventilation systems require custom-fabricated duct work. This means increased manufacturing costs for tooling and installation as well as maintenance. A low-cost molding system that does not require elaborate assembly is needed. Giddons and Taylor developed a cost-effective and efficient air circulation system for vehicles formed by rotational molding. The rotational molding can be multilayered and includes foam layers for functional improvements. The foam is created as separate layers within the cavity formed by the inner and outer solid plastic skins. The foams layers are formed so as to leave a continuous, air-filled cavity within and throughout the body walls. The rotomolded body assembly consists of lower and upper bodies that are joined or fixed together after molding. Candidate resins include polyethylene, polyamides, polypropylene and their copolymers or blends.

Conditioning Preforms

U.S. Patent 9,358,719 (June 7, 2016), “Apparatus and Method of Producing Plastics Material Containers,” Konrad Senn, Florian Wickenhoefer and Ulrich Lappe (Krones AG, Neutraubling, Germany).

Blow molding containers require forming preforms and, later, blow molding the containers. Sometimes, there is a considerable lag between preform fabrication and the final blow molding step. This results in degraded preforms leading to preforms with different properties during blowing, resulting in defective containers and discards. Senn, Wickenhoefer and Lappe developed a storage and conditioner for preforms with a tempering space before molding. The preforms can be treated and heating so that the condition, including temperature, is substantially constant for molding. The preforms needs to be kept in storage at least 15 minutes and the final preform temperatures should not vary more than 2˚ C.  

Strain Hardening Nanocomposites

U.S. Patent 9,358,730 (June 7, 2016), “Dynamic Strain Hardening in Polymer Nanocomposites,” Pulickel M. Ajayan and Brent Joseph Carey (William Marsh Rice University, Houston, Texas, USA).

Polymeric nanocomposites often lack stiffness or strength which cannot be easily enhanced. Ajayan and Carey enhanced stiffness by 50 to 30% with a dynamic stress. These composites consist of a polymer matrix and nanofillers with an interphase between matrix and fillers. Stiffness and strength of the composite can be increased permanently in response to the applied stress. It also increases the storage modulus, decreases the loss modulus and loss tangent. In these cases, the applied stress rearranges the interphase. This stress can be mechanical dynamic, static or cyclical stress. The nanofillers include carbon nanotubes, graphite, carbon black, nanofibers and nanoparticles. The polymers range from polyethylene to polyimides, as well as elastomers.

Stretch Film

U.S. Patent 9,358,760 (June 7, 2016), “Prestretched Agricultural Stretch Wrap Film,” Michael Huyghe (Combipac BV, Hardenberg, Netherlands).

Prestretched agricultural stretch wrap films have a number of drawbacks, including air and water penetration and strength. The adhesion between layers is often poor, permitting oxygen diffusion and degradation. Huyghe developed a prestretched agricultural stretch wrap film for baling grass, maize, sugar beet pulp, malt, straw or household refuse. This film is produced by prestretching a coextruded polyethylene blown film with two layers. This film must retain an elongation capability in the longitudinal direction of at least 310% so that a force of less than 6 N is required to stretch the film by 75% in the longitudinal direction. This material is a two-layer, coextruded film from linear low density polyethylene (LLDPE) and low density polyethylene (LDPE) with ethylene vinyl acetate (EVA), ethylene butyl acrylate (EBA) or ethyl methacrylate (EMA).

A Better Polypropylene for Capacitors

U.S. Patent 9,353,203 (May 31, 2016), “Process for the Preparation of Polypropylene with Improved Productivity,” Wolfgang Neissl, Dietrich Gloger, Thomas Horill, Martina Sandholzer and Gregory Potter (Borealis AG, Vienna, Austria).

Polypropylene is the material of choice for film capacitors because it lacks polar groups that orient under electrical stress. However, in case a Ziegler-Natta catalyst is used in polymerizing the resin, considerable amounts of polar residues, such as chlorine, aluminium, titanium, magnesium or silicon remain. Thus the resin must be cleaned by washing, which is time consuming and costly. Neissl et al developed a sequential polymerization process using at least two polymerization reactors connected in series with a Ziegler-Natta catalyst. The first reactor is a slurry reactor and the second stage is a gas-phase reactor with fluidized bed. The result is a resin with very low catalyst residue that does not require a final washing step and can be used directly to form capacitors.

Medical Implants

U.S. Patent 9,345,806 (May 24, 2016), “Manufacture of Medical Implants,” Claudio Tonelli, Piero Gavezotti and Ritalba Lamendola (Solvay Solexis SpA, Bollate, Italy). 

Extensive investigations have been undertaken over many years to find materials that will be compatible with body fluids. Fluorochemicals are useful but they tend to diffuse into tissue when contacted with body fluids. Tonelli, Gavezotti and Lamendola produced medical implants by reacting a mixture of nonfunctional, monofunctional and bifunctional perfluoropolyethers with hydroxyl terminal groups. The high functionality developed a network that prevents chemical extraction by biological fluids. Examples include fluorinated polyurethane polyethers and fluorinated polyesters.

Increasing Polyethylene Melt Strength

U.S. Patent 9,346,897 (May 24, 2016), “Peroxide-Treated Metallocene-based Polyolefins with Improved Melt Strength,” Lili Cui, Ashish M. Sukhadia and Vivek Rohatgi (Chevron Phillips Chemical Co. LP, The Woodlands, Texas, USA).

Many applications of polyolefin films such as linear low density polyethylene are large-scale applications such as agriculture. However, large-scale processing is a problem because of the low melt strength of polyethylene resins. Cui, Sukhadia and Rohatgi developed ethylene-based polymers with good melt strength for blown film processing without degrading properties. These resins are produced by treating a metallocene-catalyzed resin with peroxide. The base resin is mixed with the peroxide compound at the melt processing temperature from 120˚ to 300˚ C. The base resin may be fluff, powder, granulate, pellet, solution, slurries or emulsions. A resin masterbatch of the peroxide can be mixed with base resin after melting with good results.