scholarly journals Strain-Induced Form Transition and Crystallization Behavior of the Transparent Polyamide

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1028
Author(s):  
Chenxu Zhou ◽  
Siyuan Dong ◽  
Ping Zhu ◽  
Jiguang Liu ◽  
Dujin Wang ◽  
...  
Keyword(s):  
Crystalline Structure ◽  
Crystallization Behavior ◽  
Heating Process ◽  
Stable Form ◽  
X Ray Diffraction ◽  
Preparation Methods ◽  
Strain Induced Crystallization ◽  
Crystal Transition ◽  
Stretching Deformation ◽  
Induced Crystallization

A transparent polyamide, poly(4,4′-aminocyclohexyl methylene dodecanedicarboxylamide) (PAPACM12), was studied and characterized by in situ wide-angle X-ray diffraction (WAXD) to establish the relationship between its crystallization behavior, crystalline form transition under external fields, and macroscopic properties. During the heating process, cold crystallization occurred and increased, and there was no form transition below the melting point. During the isothermal process, PAPACM12 exhibited the same crystalline structure as that during the heating process. The crystalline structure of PAPACM12 was attributed to α-form crystal, which is the stable form, according to the WAXD diffraction peaks of the conventional AABB-type polyamides. During stretching deformation, the crystal transition from α-form to γ-form and strain-induced crystallization were observed to contribute to the PAPACM12 with higher breaking strength and elongation. This study firstly determine the crystalline structure of transparent polyamides, and then the controlled strain-induced crystallization and transformation are demonstrated to be effective preparation methods for polyamides with high properties.

New insights into reinforcement mechanism of nanoclay-filled isoprene rubber during uniaxial deformation by in situ synchrotron X-ray diffraction

RSC Advances ◽  
2015 ◽  
Vol 5 (32) ◽  
pp. 25171-25182 ◽  
Author(s):  
Xuan Fu ◽  
Guangsu Huang ◽  
Zhengtian Xie ◽  
Wang Xing
Keyword(s):  
Crystallization Behavior ◽  
Vital Role ◽  
Uniaxial Deformation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Reinforcement Mechanism ◽  
Strain Induced Crystallization ◽  
Induced Crystallization ◽  
Isoprene Rubber

The existence of a denser network domain formed by incorporation of filler and its vital role in determining the strain-induced crystallization behavior of nanocomposites is proved by in situ synchrotron X-ray diffraction characterization.

scholarly journals Effect of Stretching Rate on Tensile Response and Crystallization Behavior of Crosslinked Natural Rubber

2021 ◽  
Vol 17 (3) ◽  
pp. 217-225
Author(s):  
Abdulhakim Masa ◽  
Nabil Hayeemasae ◽  
Siriwat Soontaranon ◽  
Mohd Hanif Mohd Pisal ◽  
Mohamad Syahmie Mohamad Rasidi
Keyword(s):  
Stress Response ◽  
Natural Rubber ◽  
Deformation Rate ◽  
Crystallization Behavior ◽  
Tensile Deformation ◽  
Chain Orientation ◽  
Tensile Response ◽  
Lower Strain ◽  
Strain Induced Crystallization ◽  
Induced Crystallization

The performance of natural rubber (NR) relies heavily on the microstructural changes during deformation. This has brought to significant change in the stress response of NR. Besides, the stretching rate may also affect the stress response of NR. In this study, effects of stretching rate on tensile deformation and strain-induced crystallization of crosslinked NR were investigated. Results indicated that increasing the strain rate has increased the stress at given strain where the onset of strain-induced crystallization was shifted to a lower strain. The crystallinity of the crosslinked NR was shown to be higher at a high stretching rate and it corresponded well with the tensile response. The results clearly confirm that chain orientation and crystallization became stronger with increasing deformation rate. The study also suggests that the deformation could improve distribution of crosslinked network structures.

scholarly journals Influence of Temperature on Mechanical Properties of P(BAMO-r-THF) Elastomer

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2507
Author(s):  
Jinxian Zhai ◽  
Hanpeng Zhao ◽  
Xiaoyan Guo ◽  
Xiaodong Li ◽  
Tinglu Song
Keyword(s):  
Mechanical Properties ◽  
X Ray Diffraction ◽  
Polymeric Chains ◽  
Different Temperatures ◽  
Influence Of Temperature On ◽  
Strain Induced Crystallization ◽  
Thermal Histories ◽  
Static Conditions ◽  
The Relationship ◽  
Induced Crystallization

The relationship between temperature and the mechanical properties of an end cross-linked equal molar random copolyether elastomer of 3,3-bis(azidomethyl)oxetane and tetrahydrofuran (P(BAMO-r-THF)) was investigated. During this investigation, the performances of two P(BAMO-r-THF) elastomers with different thermal histories were compared at different temperatures. The elastomer as prepared at 20 °C (denoted as S0) exhibited semi-crystallization morphology. Wide angle X-ray diffraction analysis indicated that the crystal grains within elastomer S0 result from the crystallization of BAMO micro-blocks embedded in P(BAMO-r-THF) polymeric chains, and the crystallinity is temperature irreversible under static conditions. After undergoing a heating-cooling cycle, this elastomer became an amorphous elastomer (denoted as S1). Regarding mechanical properties, at 20 °C, break strains and stresses of 315 ± 22% and 0.46 ± 0.01 MPa were obtained for elastomer S0; corresponding values of 294 ± 6% and 0.32 ± 0.02 MPa were obtained for elastomer S1. At −40 °C, these strains and stresses simultaneously increased to 1085 ± 21% and 8.90 ± 0.72 MPa (S0) and 1181 ± 25% and 10.23 ± 0.44 MPa (S1), respectively, owing to the strain-induced crystallization of BAMO micro-blocks within the P(BAMO-r-THF) polymeric chains.

In situ characterization of strain-induced crystallization of natural rubber by synchrotron radiation wide-angle X-ray diffraction: construction of a crystal network at low temperatures

Soft Matter ◽  
2019 ◽  
Vol 15 (4) ◽  
pp. 734-743 ◽  
Author(s):  
Pinzhang Chen ◽  
Jingyun Zhao ◽  
Yuanfei Lin ◽  
Jiarui Chang ◽  
Lingpu Meng ◽  
...  
Keyword(s):  
Low Temperatures ◽  
Structural Evolution ◽  
X Ray Diffraction ◽  
In Situ Characterization ◽  
X Ray ◽  
Crystal Network ◽  
Strain Induced Crystallization ◽  
Induced Crystallization

The structural evolution of NR during stretching at −40 °C and in the strain–temperature space.

scholarly journals The Orientation of Strain-Induced Crystallites in Uniaxially-Strained, Thin and Wide Bands Made from Natural Rubber

Crystals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 294 ◽  
Author(s):  
Konrad Schneider ◽  
Matthias Schwartzkopf
Keyword(s):  
Natural Rubber ◽  
Pure Shear ◽  
Orientation Distribution ◽  
Thin Strip ◽  
X Ray Diffraction ◽  
Reinforcing Effect ◽  
X Ray ◽  
Crack Tips ◽  
Strain Induced Crystallization ◽  
Induced Crystallization

Vulcanized natural rubber (unfilled and filled with 20 phr carbon black) is strained. We suppress the macroscopic formation of fiber symmetry by choosing strip-shaped samples ("pure-shear geometry") and investigate the orientation of the resulting crystallites by two-dimensional wide-angle X-ray diffraction (WAXD), additionally rotating the sample tape about the straining direction. Indications of a directed reinforcing effect of the strain-induced crystallization (SIC) in the thin strip are found. In the filled material fewer crystallites are oriented and the orientation distribution of the oriented crystallites is less perfect. The results confirm, that it is important for the evaluation of crystallinity under deformation to check, whether fiber symmetry can be assumed. This has consequences in particular on the quantitative interpretation of space-resolved scanning experiments in the vicinity of crack tips. Furthermore it raises the question, whether there is an asymmetric reinforcing effect of the SIC in the vicinity of crack tips inside natural rubber.

Strain-induced crystallization behavior of phenolic resin crosslinked natural rubber/clay nanocomposites

2015 ◽  
Vol 132 (39) ◽  
pp. n/a-n/a ◽  
Author(s):  
Abdulhakim Masa ◽  
Sougo Iimori ◽  
Ryota Saito ◽  
Hiromu Saito ◽  
Tadamoto Sakai ◽  
...  
Keyword(s):  
Natural Rubber ◽  
Crystallization Behavior ◽  
Phenolic Resin ◽  
Clay Nanocomposites ◽  
Strain Induced Crystallization ◽  
Induced Crystallization

Probing the Nature of Strain-Induced Crystallization in Polyisoprene Rubber by Combined Thermomechanical and In Situ X-ray Diffraction Techniques

2005 ◽  
Vol 38 (16) ◽  
pp. 7064-7073 ◽  
Author(s):  
Shigeyuki Toki ◽  
Igors Sics ◽  
Benjamin S. Hsiao ◽  
Masatoshi Tosaka ◽  
Sirilux Poompradub ◽  
...  
Keyword(s):  
X Ray Diffraction ◽  
X Ray ◽  
Strain Induced Crystallization ◽  
Induced Crystallization

Preparation and Structure Analysis of Noncrystalline Granular Starch

2010 ◽  
Vol 6 (4) ◽  
Author(s):  
Peiling Liu ◽  
Benshan Zhang ◽  
Qun Shen ◽  
Xiaosong Hu ◽  
Wenhao Li
Keyword(s):  
Thermal Treatment ◽  
Crystalline Structure ◽  
Chemical Method ◽  
Physical Method ◽  
Maize Starch ◽  
X Ray Diffraction ◽  
Preparation Methods ◽  
Peculiar Form ◽  
Freeze Dried ◽  
Better Than

Noncrystalline granular (NCG) starch is a peculiar form of starch. The granules have granular shape but no crystalline structure. It is a middle state between native semi-crystal structure and paste. The conception of NCG starch was presented and its preparation methods for native maize starch were explored. Cross-linking by chloroepoxy propane was adopted as the chemical method while ethanol treatment was adopted as the physical method. Cross bonds and ethanol were both able to protect starch granules from swelling while thermal treatment was able to destroy crystalline structure of the granules. The structure of granule was observed by polarization microscope and scanning electron microscopy (SEM). Change from crystalline to noncrystalline structure was confirmed by X-ray diffraction (XRD). It indicated that preparation of NCG starch with the physical method was better than chemical method. The detailed conditions were: maize starch (40%, w/w) was slurried in 50%-ethanol, underwent thermal treatment at 85°C for 2 minutes, washed with anhydrous ethanol (2000 ml), and freeze dried.

Sign in / Sign up

Export Citation Format

Share Document