The present invention provides a low molecular mass PPF polymer (and related methods) that is suitable for 3D printing and other polymer device fabrication modalities and can be made inexpensively in commercially reasonable quantities. These novel low molecular mass PPF polymers have a low molecular mass distribution (.sub.m) and a wide variety of potential uses, particularly as a component in resins for 3D printing of medical devices. The ability to produce low .sub.m PPF creates a new opportunity for reliable GMP production of PPF. It provides low cost synthesis and scalability of synthesis, blending of well-defined mass and viscosity PPF, and reduced reliance on solvents or heat to (a) achieve mixing of 3D printable resins or (b) and flowability during 3D printing. These PPF polymers are non-toxic, degradable, and resorbable and can be used in tissue scaffolds and medical devices that are implanted within a living organism.

The present invention provides a low molecular mass PPF polymer (and related methods) that is suitable for 3D printing and other polymer device fabrication modalities and can be made inexpensively in commercially reasonable quantities. These novel low molecular mass PPF polymers have a low molecular mass distribution (.sub.m) and a wide variety of potential uses, particularly as a component in resins for 3D printing of medical devices. The ability to produce low .sub.m PPF creates a new opportunity for reliable GMP production of PPF. It provides low cost synthesis and scalability of synthesis, blending of well-defined mass and viscosity PPF, and reduced reliance on solvents or heat to (a) achieve mixing of 3D printable resins or (b) and flowability during 3D printing. These PPF polymers are non-toxic, degradable, and resorbable and can be used in tissue scaffolds and medical devices that are implanted within a living organism.

Polymer powders useful for additive manufacturing may be made by contacting carbon dioxide and a crystallizable polymer having at least one carbonyl, sulfur oxide or sulfone group; permeating the carbon dioxide into the polymer for a crystallizing time sufficient to induce crystallization forming an induced crystalized polymer; removing the carbon dioxide; and forming induced crystalized polymer particles having a D90 particle size of at most 300 micrometers and average particle size of 1 micrometer to 100 micrometers equivalent spherical diameter. The carbon dioxide is desirably supercritical carbon dioxide for at least a portion of the crystallizing time. The polymer powders upon heating during additive manufacturing may result in a polymer having less crystallinity or become amorphous.

A polyethylene terephthalate purification apparatus comprises at least a reactor (4) which houses the plastic material to be purified, an opening connected to a vacuum pump, stirrers (16) to ensure the stirring of the plastic material inside of the reactor (4) and a heating mechanism comprising a microwave heating device to promote the excitation of the polar molecules.

A polyethylene terephthalate purification apparatus comprises at least a reactor (4) which houses the plastic material to be purified, an opening connected to a vacuum pump, stirrers (16) to ensure the stirring of the plastic material inside of the reactor (4) and a heating mechanism comprising a microwave heating device to promote the excitation of the polar molecules.

The present invention is directed to an improved purification process using additive and activated carbon for purifying resorbable polymers suitable for industrial manufacturing. The metal catalyst concentration in the purified resorbable polymers of this invention is preferably less than 1 ppm. The method can be used to obtain high molecular weight polymers that are substantially metal free.

The present invention is directed to an improved purification process using additive and activated carbon for purifying resorbable polymers suitable for industrial manufacturing. The metal catalyst concentration in the purified resorbable polymers of this invention is preferably less than 1 ppm. The method can be used to obtain high molecular weight polymers that are substantially metal free.

The invention refers to a Process for preparing a bio-resorbable polyester the form of a powder with a bulk density of 0.3 g/ml or more, a tapped density of 0.4 g/ml or more and a specific surface area of 2.0 m.sup.2/g or less comprising the steps a. dissolving a bio-resorbable polyester in a first solvent to form a polymer solution, b. contacting the polymer solution with a second solvent which is a non-solvent for the bioresorbable polyester and which is mainly water to result the precipitation of the bio-resorbable polyester in the form of a wet polymer mass, c. pre-drying the wet polymer mass at a temperature below the T.sub.gO of the bio-resorbable polyester, d. comminuting the pre-dried polymer mass to polymer particles with a size below 10 mm, e. drying the comminuted polymer particles below the T.sub.gO of the bio-resorbable polyester to a residual water content of 1% or less by weight/weight, f. post-treatment of the polymer particles from step e at a temperature in the range from the T.sub.gO to the T.sub.gE of the bio-resorbable polyester, g. comminuting the polymer particles from step f to a powder with a particle size of d.sub.50 of 1-300 μm and d.sub.90 of more than 30 and up to 3000 μm.

The invention refers to a Process for preparing a bio-resorbable polyester the form of a powder with a bulk density of 0.3 g/ml or more, a tapped density of 0.4 g/ml or more and a specific surface area of 2.0 m.sup.2/g or less comprising the steps a. dissolving a bio-resorbable polyester in a first solvent to form a polymer solution, b. contacting the polymer solution with a second solvent which is a non-solvent for the bioresorbable polyester and which is mainly water to result the precipitation of the bio-resorbable polyester in the form of a wet polymer mass, c. pre-drying the wet polymer mass at a temperature below the T.sub.gO of the bio-resorbable polyester, d. comminuting the pre-dried polymer mass to polymer particles with a size below 10 mm, e. drying the comminuted polymer particles below the T.sub.gO of the bio-resorbable polyester to a residual water content of 1% or less by weight/weight, f. post-treatment of the polymer particles from step e at a temperature in the range from the T.sub.gO to the T.sub.gE of the bio-resorbable polyester, g. comminuting the polymer particles from step f to a powder with a particle size of d.sub.50 of 1-300 μm and d.sub.90 of more than 30 and up to 3000 μm.

A method for stabilizing a condensed phase composition in a process of manufacturing a polyester from cyclic ester monomer comprising the steps of devolatilizing a reaction mixture, which contains i) at least one polymerizable cyclic ester, ii) at least one catalyst and optionally at least one initiator, to produce a vapor stream and a molten residue, wherein the vapor stream includes mainly i) the at least one polymerizable cyclic ester and ii) the at least one catalyst and/or the at least one initiator and/or a reaction product or a residue of the at least one catalyst and/or the at least one initiator and condensing the vapor stream to form the condensed phase composition, wherein at least one polymerization inhibitor is added as stabilizer to the reaction mixture and/or to the condensed phase composition in an amount so that the degree of conversion of the polymerizable cyclic ester in the condensed phase composition is not more than 15%, wherein the degree of conversion is 100.square-solid. (c0−C.sub.F)/c.sub.0, wherein c.sub.0 is the initial concentration of the cyclic ester in the condensed phase composition obtained by the condensation of the vapor stream and C.sub.F is the concentration of the cyclic ester in the condensed phase composition after addition of 150 ppm of tin octoate as catalyst and of 100 mmol/kg of ethyl-hexanol as initiator to the condensed phase composition and a subsequent heat treatment of condensed phase composition under inert atmosphere conditions for 12 hours at 160° C.