The present application relates to a supercritical fluid injection foaming polylactide foam material and a preparation method therefor. The method includes: first obtaining a surface-modified cellulose nanofiber aqueous solution; then melting and blending the cellulose nanofiber aqueous solution and a polylactide twice; passing same through extrusion, cooling under water, and granulation so as to obtain a polylactide/cellulose nanofiber composite material; then plasticizing and melting the polylactide/cellulose nanofiber composite material in a microporous foaming injection molding machine; uniformly mixing same with a supercritical fluid foaming agent in the injection molding machine; injecting same into a mold cavity; and subjecting the resultant to post-treatment so as to obtain a polylactide foam material. The polylactide foam material has a sandwich structure, in which two outer surface layers are solid layers that do not contain any foam, and the sandwiched layer is a foam layer having a cellular structure.

A semicrystalline polyketone powder useful for additive manufacturing may be made by dissolving a polyketone having differential scanning calorimetry (DSC) monomodal melt peak, at a temperature above 50° C. to below the melt temperature of the polyketone, precipitating the dissolved polyketone by cooling, addition of a nonsolvent or combination thereof. The method may be used to form polyketones having a DSC melt peak with an enthalpy greater than the starting polyketone.

The present invention relates to a method preparing a highly functional foam by a physical foaming process (physical blowing agent-based foaming) used to prepare a midsole of a shoe, and relates to a technology that is environmentally friendly because a chemical foaming agent is not used and is capable of preparing a foam with improved physical properties at a low cost by shortening a processing time. To this end, according to the present invention, a physical foaming process of preparing a foam by using a foaming press provided with a cavity includes: an injecting step of injecting a foaming compounding resin into the cavity; a closing step of closing the cavity by using the foaming press; a gas injecting step of injecting gas into the cavity; an atmospheric pressure maintaining step of dissolving the gas in the foaming compounding resin by maintaining the inside of the cavity at a constant pressure; and a foaming step of performing foaming by opening the cavity so that the inside of the cavity is depressurized.

The present application relates to a chain extender masterbatch for PET extrusion foaming, preparation method therefor, and a use thereof. The masterbatch is mainly prepared by the following components in parts by weight: 5-30 parts of PMDA, 25-90 parts of PBT, 5-70 parts of POE+POE-g-GMA, in which POE accounts for 0-85% of POE+POE-g-GMA by weight; a melting temperature of PBT is 170-225° C. The preparation method includes melting and mixing the above components at a melting temperature of 180-230° C. and a screw speed of 100-500 rpm, and air cooling strand granulating or air cooling die face granulating. The masterbatch can be used in foaming processes of fiber grade PET, film grade PET, bottle grade PET, engineering plastic grade PET and recycled PET.

A molded foam that can be easily taken out of split mold blocks is provided. According to an aspect of the present disclosure, a molded foam (1) is obtained by clamping, with split mold blocks, foamed resin obtained by melting and kneading a polyethylene-based resin, wherein the molded foam (1) has a MFR (190° C., g/10 min) of less than 0.8, or the polyethylene-based resin has a MFR (190° C., g/10 min) of not more than 1.0.

A resin sheet includes the porous structure. The porous structure is configured to adjust transmission of a millimeter wave. The porous structure has a relative permittivity varying in a thickness direction of the resin sheet such that a difference between average relative permittivities in two adjacent layer portions is a predetermined value or less, the layer portions each having a particular thickness smaller than a wavelength of the millimeter wave. The porous structure includes a boundary portion being one of the layer portions, the boundary portion having a maximum average relative permittivity. The relative permittivity increases in stages from end portions of the porous structure toward the boundary portion, the end portions being defined in the thickness direction of the resin sheet.

Disclosed is an organic amine salt foaming agent, that is, a composite polyurethane foaming agent, comprising: 1) hexafluorobutene; and 2) an alkanolamine salt mixture (MAA), the alkanolamine salt mixture (MAA) contains an organic amine salt compound having the following general formula (I): A.sup.n−[B.sup.m+].sub.p (I); wherein A.sup.n− is one or two or three selected from the following anions: (b) carbonate: CO.sub.3.sup.2−; (c) formate: HCOO.sup.−; (d) bicarbonate: HO—COO.sup.−. A polyurethane foaming method using carbon dioxide and an organic amine in combination is also disclosed, in which carbon dioxide is added to a polyurethane composition for foaming. A method for preparing an alkanolamine carbonate salt with low water content from ammonium carbonate and an epoxide is additionally disclosed, in which a liquid alkanolamine salt mixture is used as a dispersion medium or as a solvent for reaction raw material.

A process for producing a flexible foam includes introducing a masterbatch material into an extruder, the masterbatch material consisting essentially of one or more thermoplastic polymers that are recycled, recyclable, biodegradable, and/or compostable, mixing an inert gas with the masterbatch material, extruding the masterbatch material through the extruder to form a polymer melt, passing the polymer melt through a die to form an extrudate, and allowing the extrudate to expand into a foam.

A resin sheet includes a porous structure. The porous structure is configured to adjust transmission of a millimeter wave. The porous structure has a relative permittivity varying in stages in a thickness direction of the resin sheet from a plane on which the millimeter wave is incident, the relative permittivity varying such that a difference between average relative permittivities in two adjacent layer portions is a predetermined value or less, the layer portions each having a particular thickness smaller than a wavelength of the millimeter wave. The porous structure has, as pores, only pores each having a pore diameter equal to or less than 10% of the wavelength of the millimeter wave.

A microporous polyolefin (PO) foamed material is provided, which is prepared from a PO composition through a foaming process, where the PO composition includes a PO and an additive composition, and with the PO composition as 100 parts by mass, the additive composition accounts for 3 to 20 parts by mass; the additive composition includes a functional additive A; the functional additive A has a molecular formula of R—(OCH.sub.2CH.sub.2).sub.xOH, where R is an aralkyl group, a straight alkyl chain, or a branched alkyl chain that has 5 to 60 carbon atoms, and x is 1 to 20; and an absolute value of a solubility parameter difference between the PO and the functional additive A is greater than or equal to 1 (J/cm.sup.3).sup.1/2 and less than or equal to 5 (J/cm.sup.3).sup.1/2 . When the method is used for PO foaming, the foaming efficiency is greatly improved, thereby reducing a production cost.