Thermoreversible Cross-Linking of Maleated Ethylene/Propylene Copolymers Using Hydrogen-Bonding and Ionic Interactions

2006 ◽  
Vol 39 (9) ◽  
pp. 3441-3449 ◽  
Author(s):  
C. X. Sun ◽  
M. A. J. van der Mee ◽  
J. G. P. Goossens ◽  
M. van Duin
Keyword(s):  
Hydrogen Bonding ◽  
Ionic Interactions ◽  
Cross Linking ◽  
Ethylene Propylene

Thermoreversible Crosslinking of Maleated Ethylene/Propylene Rubber Using Ionic Interactions, Hydrogen Bonding and a Combination Thereof

2008 ◽  
Vol 81 (1) ◽  
pp. 96-109 ◽  
Author(s):  
M. A. J. van der Mee ◽  
J. G. P. Goossens ◽  
M. van Duin
Keyword(s):  
Mechanical Properties ◽  
Hydrogen Bonding ◽  
Room Temperature ◽  
Microphase Separation ◽  
Distinct Advantage ◽  
Ionic Interactions ◽  
Ethylene Propylene ◽  
Bonded Materials ◽  
Compression Set ◽  
High Degree

Abstract Maleated ethylene/propylene copolymer (MAn-g-EPM) was thermoreversibly crosslinked using different routes, i.e. ionic interactions (ionomers), hydrogen bonding and a combination thereof. Microphase separation into polar MAn-rich aggregates occurs for MAn-g-EPM and all crosslinked materials, which act as physical crosslinks. The crosslink density does not change upon modification, but the strength of the aggregates is significantly increased, resulting in improved mechanical properties. All materials except the potassium ionomer with high degree of neutralization (DN) could be remolded into homogeneous and smooth films without chemical changes, indicating that the crosslinks are truly thermoreversible. A comparison of the mechanical properties, i.e. tensile properties and compression set at room temperature, for the different crosslinking routes showed that the poorest properties are obtained for hydrogen-bonded materials. The potassium ionomer with high DN has the best properties by far, but is difficult to process. Comparable mechanical properties are obtained for zinc ionomers, potassium ionomers with low DN and amide-salts, which combine ionic interactions and hydrogen bonding. The amide-salts have a distinct advantage in processing over the ionomers, since they can be compression molded at much lower temperatures, although high temperatures should be avoided because of irreversible imide formation.

Novel Hydrogen-Bonding Cross-Linking Aggregation-Induced Emission: Water as a Fluorescent “Ribbon” Detected in a Wide Range

2017 ◽  
Vol 9 (18) ◽  
pp. 15744-15757 ◽  
Author(s):  
Ani Wang ◽  
Ruiqing Fan ◽  
Yuwei Dong ◽  
Yang Song ◽  
Yuze Zhou ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Cross Linking ◽  
Aggregation Induced Emission ◽  
Wide Range

THERMOREVERSIBLE CROSS-LINKING MALEIC ANHYDRIDE GRAFTED CHLOROBUTYL RUBBER WITH HYDROGEN BONDS (COMBINED WITH IONIC INTERACTIONS)

2014 ◽  
Vol 87 (3) ◽  
pp. 459-470 ◽  
Author(s):  
Lin Li ◽  
Jin Kuk Kim
Keyword(s):  
Hydrogen Bonds ◽  
Maleic Anhydride ◽  
Ionic Interactions ◽  
Cross Linking ◽  
External Energy ◽  
Scanning Calorimetry ◽  
Ionic Bonds ◽  
Cross Links ◽  
Ionic Hydrogen Bonds ◽  
Chlorobutyl Rubber

ABSTRACT Thermoreversible cross-linking polymers are designed based on reversible cross-linking bonds. These bonds are able to reversibly dissociate and associate upon the input of external energy, such as heat or light. Reprocessibility is possible for this kind of material. The objective was to thermoreversibly cross-link maleic anhydride grafted chlorobutyl rubber (MAH-g-CIIR) via a reaction with octadecylamine, with an excess to obtain amide-salts, which form both hydrogen bonds and ionic interactions. X-ray diffraction experiments showed the presence of microphase-separated aggregates that acted as physical cross-links for both the MAH-g-CIIR precursor and amide-salts. The tensile properties were improved by converting MAH-g-CIIR to amide-salts, because of the combination of hydrogen bonding and ionic interactions. The cross-linked materials could be repeatedly compression molded at 155 °C into homogeneous films. The differential scanning calorimetry curves and Fourier transform infrared spectra indicate that hydrogen bonds are of a thermoreversible nature, but the recovery of ionic bonds is impossible. After treatment with heating-cooling for up to three cycles, the tensile strength of the thermoreversible cross-linking CIIR was greatly reduced. The gradual reduction in the effectiveness of the ionic-hydrogen bonds is the major contribution to the reprocessibility of these materials.

A fluorescent “glue” of water triggered by hydrogen-bonding cross-linking

2016 ◽  
Vol 4 (47) ◽  
pp. 11050-11054 ◽  
Author(s):  
Dejia Wang ◽  
Hongwei Zhao ◽  
Hongjuan Li ◽  
Shiguo Sun ◽  
Yongqian Xu
Keyword(s):  
Hydrogen Bonding ◽  
Organic Solvents ◽  
Organic Molecule ◽  
Linear Range ◽  
Cross Linking ◽  
The Novel ◽  
Aggregation Induced Emission ◽  
Small Organic Molecule ◽  
Wide Linear Range ◽  
Trace Water

As a “glue” of water, a small organic molecule with the novel hydrogen-bonding cross-linked aggregation-induced emission (AIE) property was designed to detect trace water, displaying a wide linear range (0–40%, v/v) in most of the organic solvents.

Elongation at Break as a Measure of Cross-Link Density in Vulcanized Elastomers

1966 ◽  
Vol 39 (3) ◽  
pp. 726-739 ◽  
Author(s):  
E. DiGiulio ◽  
G. Bellini ◽  
G. V. Giandinoto
Keyword(s):  
Crosslink Density ◽  
Cross Linking ◽  
Total Degree ◽  
Cross Link ◽  
Elongation Ratio ◽  
Elongation At Break ◽  
Ethylene Propylene ◽  
First Approximation ◽  
Link Density ◽  
Cross Link Density

Abstract After recalling the reaction mechanism suggested for the crosslinking of ethylene propylene copolymers with organic peroxides, the authors consider the relation between concentration of curing agent and crosslink density. It is experimentally found that, as a first approximation, the elongation ratio at break of vulcanizates (unfilled or filled with small quantities of carbon black) is a function of molar concentration of peroxide only: αR=K/P1/2 This relation can be theoretically justified on the basis of the extensibility of polymer chain segments and of the criterion for rupture originally put forward by Taylor and Darin. By applying the above relation to ethylene propylene copolymers it is possible to evaluate the influence of the chain-splitting reaction during cross-linking. The reciprocal of the square of elongation ratio at break (1/αR2) measures the total degree of crosslinking.

Synthesis, Characterization and Dynamic Mechanical Property of PU Elastomers with Cross-Linked Hard Segments

2011 ◽  
Vol 197-198 ◽  
pp. 1205-1212
Author(s):  
Xiao Long Ning ◽  
Qiang Xu ◽  
Gui You Wang
Keyword(s):  
Mechanical Property ◽  
Hydrogen Bonding ◽  
Crosslink Density ◽  
Dynamic Mechanical Property ◽  
Cross Linking ◽  
Curing Agent ◽  
Diphenylmethane Diisocyanate ◽  
Ft Ir ◽  
Hard Segments ◽  
Lower Temperature

A series of cross-linked polyurethane(PU) elastomer samples with various crosslink density were synthesized from polyether diol(PPG2000), 4,4’-diphenylmethane diisocyanate(MDI), 1,4-butanediol(BDO) , trimethylolpropane (TMP) and glycerin. The cross-linking density of the PU elastomers was calculated by Flory–Rehner equation. The degree of hydrogen bonding, the microstructure and the morphologies of these PU materials were characterized by means of FT-IR, DSC and DMA. The experimental results showed that the PU elastomers containing a small amount of crosslink agent ( TMP or glycerin ) may make tanδ to a very low value above the ambient temperature. The PU elastomer samples using glycerin as curing agent can make tanδ to a low value in a lower temperature compared with the ones using TMP as curing agent.

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