South China University of Technology

Guangdong Huayi Plumbing Fittings Industry Co., Ltd.

Hongwei Ma

Chao Yang

Yanfei Ding

Xuehui Li

Jinxing Long

Zhenping Cai

Weijie Zhao

Weisi Cai

Xiao Yu

Zhangmin Li

The invention belongs to the technical field of shape memory alloys and additive manufacturing, and discloses a NiTiHf high temperature shape memory alloy with two-way shape memory effect and a 4D printing method and application thereof. The 4D printing method includes alloy powder processing, model building and substrate preheating, and 4D printing forming. The present invention patent is based on the design concept of reducing thermal gradient and the environmental friendly concept of clean production. It adopts substrate preheating combined with low laser power and low scanning speed laser powder bed fusion technology or low preheating temperature electron beam powder bed fusion technology to improve the formed alloy. The lattice compatibility with the NiTi substrate reduces the residual stress of the formed sample, and produces no cracks, no obvious holes, density ≥99%, high phase transformation temperature, excellent tensile mechanical properties and two-way shape memory effect.

NiTiHf high temperature shape memory alloy with two-way shape memory effect, and 4D printing method and application thereof

The present invention discloses a method for preparing p-hydroxycinnamate by using an ionic liquid for catalytic lignin depolymerization comprising: 1) preparation of a halogen metal-based ionic liquid: preparing the halogen metal-based ionic liquid by reacting an alkylimidazole chloride with a metal chloride by heating the same to 30&#xb0; C. to 80&#xb0; C. with stirring; and 2) catalytic depolymerization of lignin: mixing the halogen metal-based ionic liquid and lignin with an alcohol, and after Nreplacement, heating the solution to 140&#xb0; C. to 200&#xb0; C. and reacting the solution for 4-8 h while stirring to prepare high value-added chemicals with p-hydroxycinnamate as a main product. The present invention has advantages of a simple process, mild conditions, environmental kindness, and high selectivity for a main product. The ionic liquid is simple in preparation, has a good atom economy, and is recyclable. Under optimal conditions, the yield of p-hydroxycinnamate can reach 40-80 mg/g.

Method for preparing p-hydroxycinnamate by using ionic liquid for catalytic lignin depolymerization

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Guangzhou, China

Hongwei Ma