Polymer compositions with low warpage

A method of making an article of manufacture comprising shaping a polymeric composition comprising a polyolefin polymer and a nucleating agent having an average particle size of less than 2 micrometers (μm), wherein the average particle size is an equivalent spherical diameter determined by sedimentation, wherein the composition comprises 1,000 ppm to 10,000 ppm of the nucleating agent, and wherein the polyolefin polymer comprises a homopolymer, a random copolymer, an impact copolymer comprising a polypropylene homopolymer, an ethylene-propylene rubber phase, or a combination thereof, wherein the polymeric composition exhibits more homogeneous shrinkage in longitudinal and transverse directions relative to a comparable polymeric composition comprising the same polyolefin polymer and the same nucleating agent, but wherein the same nucleating agent has an average particle size greater than or equal to 2 μm, such that the polymeric composition exhibits substantially no warpage.

A method of reducing warpage in a polyolefin polymer, the method comprising adding a nucleating agent having an average particle size of less than 2 micrometers (μm) to the polyolefin polymer to form the polyolefin composition, wherein the average particle size is an equivalent spherical diameter determined by sedimentation, wherein the nucleating agent is added to the polyolefin polymer such that the nucleating agent is present in the composition in an amount from 1,000 ppm to 10,000 ppm, and wherein the polyolefin polymer comprises a homopolymer, a random copolymer, an impact copolymer comprising a polypropylene homopolymer, an ethylene-propylene rubber phase, or a combination thereof, wherein the polymeric composition exhibits more homogeneous shrinkage in longitudinal and transverse directions relative to a comparable polymeric composition comprising the same polyolefin polymer and the same nucleating agent, but wherein the same nucleating agent has an average particle size greater than or equal to 2 μm, such that the polymeric composition exhibits substantially no warpage.