Novel structures by microlayer coextrusion—talc‐filled PP, PC/SAN, and HDPE/LLDPE

Abstract

Numerous examples in the literature illustrate how the coextrusion of film with three or more polymeric layers is economically used to achieve a desirable mix of end‐use characteristics. More recently, layer‐multiplying devices permit two polymers of widely dissimilar solid‐state properties to be combined into unique microlayer and nanolayer structures with hundreds or thousands of alternating layers. If the layers are thin enough, the key properties of the constituents can combine synergistically. The microlayer structure is also an effective research tool. Because the microlayer and nanolayer structures contain large specific interfacial areas, they are ideal for fundamental studies of phenomena such as interdiffusion and adhesion. Three examples of microlayered materials with up to 1024 layers illustrate the versatility of this coextrusion process: talc‐filled PP, PC/SAN, and HDPE/LLDPE.

Probing Nanoscale Polymer Interactions by Forced‐Assembly

“…[10] Each layer can be less than 10 nm in thickness. [11,12] Although the amount of material in a single interphase between two polymer layers is very small, the layer thickness can be made comparable to the interphase dimension, and the properties of the interphase are multiplied a thousand-fold by the number of identical interphases in the assembly. This enables us to use conventional methods of polymer analysis to probe size-scale-dependent properties as nanolayers became thinner and more interphase-like.…”

Oxygen transport as a solid‐state structure probe for polymeric materials: A review

“…[71][72][73] The challenges of characterizing the small amounts of materials in nanofilms with conventional methods of polymer analysis are addressed by the multiplication of the number of thin films a 100-fold or even a 1000-fold by layermultiplying coextrusion. 74,75 The scientifically and technologically important interphase between two immiscible polymers is probed with assemblies of thousands of alternating layers of two glassy polymers, with the individual layer thickness on the nanometer size scale of the interphase. 76,77 By sensing the composite nature of the assembly, gas transport becomes a primary method for extracting the dimension and other fundamental characteristics of the interphase.…”

New class of bioinspired lenses with a gradient refractive index

“…35 The extruder temperatures were adjusted to ensure that the viscosities matched when the melts were combined in the feed block. From the feed block, the melt stream flowed through a series of layer-multiplying die elements (Fig.…”

“…35 Individual layers can be less than 10 nm thick. 36,37 The reflective characteristics of polymer forced assemblies are exploited to fabricate films with colorful iridescence, 38 with narrow band transmission (one-dimensional photonic crystals), 39 or with other optical properties.…”