A Raman study of nylon 6 annealed under high pressure

e-Polymers ◽  
2011 ◽  
Vol 11 (1) ◽  
Author(s):  
Weijie Xu ◽  
Dahu Cao ◽  
Qiang Yu
Keyword(s):  
High Pressure ◽  
Ambient Pressure ◽  
Nylon 6 ◽  
Pressure Treatment ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
High Pressure Treatment ◽  
Structure Changes ◽  
Raman Study ◽  
Hydrogen Bonded

AbstractUsing a cubic-anvil high pressure apparatus, nylon 6 samples were annealed under 400 MPa to 1.5 GPa. The structure changes of nylon 6 are studied by the methods of wide-angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC) and Raman spectra. Compared with sample prepared at ambient pressure, high pressure treatment makes the hydrogen-bonded sheets pack more closely and thus enhanced CH2 vibration out of the hydrogen-bonded sheets. After high pressure treatment, it is observed that all changes of C-C related vibration modes in nylon 6 are similar with ones in nylon series when the CH2 sequence number increased, from which it is deduced that high pressure treatment reduces the effects of amide group on the chain conformation of nylon 6.

Crystal Polymorphs and Multiple Crystallization Pathways of Highly Pressurized 1-Ethyl-3-Methylimidazolium Nitrate

2019 ◽  
Vol 72 (2) ◽  
pp. 87 ◽  
Author(s):  
Hiroshi Abe ◽  
Takahiro Takekiyo ◽  
Yukihiro Yoshimura ◽  
Nozomu Hamaya ◽  
Shinichiro Ozawa
Keyword(s):  
Differential Scanning Calorimetry ◽  
High Pressure ◽  
Room Temperature ◽  
Ambient Pressure ◽  
Optical Microscope ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Low Temperature Crystallization ◽  
Temperature Crystallization

Crystal polymorphs and multiple crystallization pathways of a room-temperature ionic liquid (RTIL) were observed only under high pressure (HP). The RTIL was 1-ethyl-3-methylimidazolium nitrate, [C2mim][NO3]. The HP-crystal polymorphs were related to conformations of the C2mim+ cation, and the HP-crystal pathways determined by the presence or absence of the planar′ (P′) conformation of the C2mim+ cation were switched at the bifurcation pressure (PB). Above PB, modulated crystal structures derived from the HP-inherent P′ conformer. Simultaneous X-ray diffraction and differential scanning calorimetry measurements, accompanied by optical microscope observations, confirmed the normal low-temperature crystallization of [C2mim][NO3] under ambient pressure.

scholarly journals A closer look into close packing: pentacoordinated silicon in a high-pressure polymorph of danburite

IUCrJ ◽  
2017 ◽  
Vol 4 (5) ◽  
pp. 671-677 ◽  
Author(s):  
Anna Pakhomova ◽  
Elena Bykova ◽  
Maxim Bykov ◽  
Konstantin Glazyrin ◽  
Biliana Gasharova ◽  
...  
Keyword(s):  
High Pressure ◽  
Inorganic Compounds ◽  
Close Packing ◽  
Hexagonal Close Packing ◽  
Pressure Treatment ◽  
Ambient Conditions ◽  
X Ray Diffraction ◽  
High Pressure Treatment ◽  
X Ray ◽  
Unusual Formation

Due to their high technological and geological relevance, silicates are one of the most studied classes of inorganic compounds. Under ambient conditions, the silicon in silicates is almost exclusively coordinated by four oxygen atoms, while high-pressure treatment normally results in an increase in the coordination from four- to sixfold. Reported here is a high-pressure single-crystal X-ray diffraction study of danburite, CaB2Si2O8, the first compound showing a step-wise transition of Si coordination from tetrahedral to octahedral through a trigonal bipyramid. Along the compression, the Si2O7groups of danburite first transform into chains of vertice-sharing SiO5trigonal bipyramids (danburite-II) and later into chains of edge-sharing SiO6octahedra (danburite-III). It is suggested that the unusual formation of an SiO5configuration is a consequence of filling up the pentacoordinated voids in the distorted hexagonal close packing of danburite-II.

Effect of High Pressure Treatment and Synthesis on Multiferroic Properties of 0.9BiFeO3-0.1SrTiO3 Ceramics

2014 ◽  
Vol 1082 ◽  
pp. 61-64
Author(s):  
Zheng Zheng Ma ◽  
Zi Peng Chen ◽  
Jian Qing Li ◽  
Hai Jun Huang
Keyword(s):  
High Pressure ◽  
Room Temperature ◽  
Single Phase ◽  
Pressure Treatment ◽  
X Ray Diffraction ◽  
High Pressure Treatment ◽  
X Ray ◽  
Multiferroic Properties ◽  
Pressure Synthesis ◽  
High Temperature High Pressure

The solid solution ceramics of 0.9BiFeO3-0.1SrTiO3 (BFST) were processed under cool-high pressure (BFST-H1, BFST-H2) and high temperature-high pressure (BFST-H3). And the high pressure synthesis with different temperature was used to prepare the sample BFST-H4 and BFST-H5. X-ray diffraction showed that these ceramics are almost of single phase. Among all the samples, the 3GPa,900°C high pressure synthesized one shows the optimal ferroelectricity at room temperature, with enhanced magnetic properties was observed.

Comparison of Ricotta cheese made by high pressure treatment with that produced by heat treatment of sweet whey

2002 ◽  
Vol 22 (5) ◽  
pp. 601-615 ◽  
Author(s):  
Souhail Besbes ◽  
Christophe Blecker ◽  
Hamadi Attia ◽  
Carine Massaux ◽  
Claude Deroanne
Keyword(s):  
Heat Treatment ◽  
High Pressure ◽  
Pressure Treatment ◽  
High Pressure Treatment ◽  
Sweet Whey

scholarly journals Effect of food processing on the antioxidant activity of flavones from Polygonatum odoratum (Mill.) Druce

2021 ◽  
Vol 16 (1) ◽  
pp. 92-101
Author(s):  
Guanghui Xia ◽  
Xinhua Li ◽  
Zhen Zhang ◽  
Yuhang Jiang
Keyword(s):  
Antioxidant Activity ◽  
High Pressure ◽  
Food Processing ◽  
Yeast Fermentation ◽  
Pressure Treatment ◽  
Processing Methods ◽  
High Pressure Treatment ◽  
Effect Of Food ◽  
The Stability

Abstract Polygonatum odoratum (Mill.) Druce (POD) is a natural plant widely used for food and medicine, thanks to its rich content of a strong antioxidant agent called homoisoflavones. However, food processing methods could affect the stability of POD flavones, resulting in changes to their antioxidant activity. This study attempts to evaluate the antioxidant activity of POD flavones subject to different processing methods and determines which method could preserve the antioxidant activity of POD flavones. Therefore, flavones were extracted from POD samples, which had been treated separately with one of the four processing methods: extrusion, baking, high-pressure treatment, and yeast fermentation. After that, the antioxidant activity of the flavones was subject to in vivo tests in zebrafish embryos. The results show that yeast fermentation had the least disruption to the antioxidant activity of POD flavones, making it the most suitable food processing method for POD. By contrast, extrusion and high-pressure treatment both slightly weakened the antioxidant activity of the flavones and should be avoided in food processing. The research results provide a reference for the development and utilization of POD and the protection of its biological activity.

scholarly journals High Pressure Treatment in Foods

Foods ◽  
2014 ◽  
Vol 3 (3) ◽  
pp. 476-490 ◽  
Author(s):  
Edwin Bello ◽  
Gerardo Martínez ◽  
Bernadette Ceberio ◽  
Dolores Rodrigo ◽  
Antonio López
Keyword(s):  
High Pressure ◽  
Pressure Treatment ◽  
High Pressure Treatment
Sign in / Sign up

Export Citation Format

Share Document