Optical transparency is an important property for a material, especially in certain fields like packaging, glazing, and displays. Existing commercial transparent polymeric materials are mostly amorphous. Semicrystalline polymers have often-superior chemical resistance and mechanical properties particularly at elevated temperatures or after solid-state drawing but they appear opaque or white in most cases. This review describes the present state-of-the-art of methodologies of fabricating optically transparent materials from semicrystalline polymers. A distinction is made between isotropic, biaxially stretched, and uniaxially stretched semicrystalline polymers. Furthermore, some functionalities of transparent nanocomposites based on semicrystalline polymers are also discussed. This review aims to provide guidelines regarding the principles of manufacturing transparent high-performance semicrystalline polymers and their nanocomposites for potential applications in fields like packaging, building, and construction, aerospace, automotive, and opto-electronics.

High performance transparent polymeric materials are of great interests in many fields including automotive and electronics. Conventional transparent plastics like polycarbonate (PC) and poly(methyl methacrylate) (PMMA) possess relatively unsatisfactory mechanical performance, while high performance polymeric systems like solid-state drawn high-density polyethylene (HDPE) typically have an opaque appearance, limiting applications where both mechanical and optical properties are required. In this study, we successfully combined high transparency and high strength in HDPE films by carefully controlling processing parameters

Hydrogel microfibers have been considered as a potential biomaterial to spatiotemporally biomimic 1D native tissues such as nerves and muscles which are always assembled hierarchically and have anisotropic response to external stimuli. To produce facile hydrogel microfibers in a mathematical manner, a novel dynamic-crosslinking-spinning (DCS) method is demonstrated for direct fabrication of size-controllable fibers from poly(ethylene glycol diacrylate) oligomer in large scale, without microfluidic template and in a biofriendly environment. The diameter of fibers can be precisely controlled by adjusting the spinning parameters. Anisotropic swelling property is also dependent on inhomogeneous structure generated in spinning process. Comparing with bulk hydrogels, the resulting fibers exhibit superior rapid water adsorption property, which can be attributed to the large surface area/volume ratio of fiber. This novel DCS method is one-step technology suitable for large-scale production of anisotropic hydrogel fibers which has a promising application in the area such as biomaterials.

The continuous production of transparent high strength ultra-drawn highdensity polyethylene films or tapes is explored using a cast film extrusion and solid-state drawing line. Two methodologies are explored to achieve such high strength transparent polyethylene films; i) the use of suitable additives like 2-(2H-benzotriazol-2-yl)-4,6-ditertpentylphenol (BZT) and ii) solid-state drawing at an optimal temperature of 105 °C (without additives). Both methodologies result in highly oriented films of high transparency (≈91%) in the far field. Maximum attainable modulus (≈33 GPa) and tensile strength (≈900 MPa) of both types of solid-state drawn films are similar and are an order of magnitude higher than traditional transparent plastics such as polycarbonate (PC) and poly(methyl methacrylate). Special emphasis is devoted to the effect of draw down and pre-orientation in the as-extruded films prior to solid-state drawing. It is shown that pre-orientation is beneficial in improving mechanical properties of the films at equal draw ratios. However, pre-orientation lowers the maximum attainable draw ratio and as such the ultimate modulus and tensile strength of the films. Potential applications of these high strength transparent flexible films lie in composite laminates, automotive or aircraft glazing, high impact windows, safety glass, and displays.

Advanced composite materials reinforced with high performance fibers like carbon, glass, aramid or ultra-high molecular weight polyethylene are widely used as lightweight materials in the fields of automotive, aerospace, sports and protection. However, nearly always these composites are opaque and/or they absorb light, which greatly limits their application in areas where high optical