Synthesis of High-Molecular-Weight Maleic Anhydride-Based Polyesters with Enhanced Properties

2020 ◽  
Vol 2 (12) ◽  
pp. 5817-5823
Author(s):  
Lan-Fang Hu ◽  
Cheng-Jian Zhang ◽  
Dan-Jing Chen ◽  
Xiao-Han Cao ◽  
Jia-Liang Yang ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Maleic Anhydride ◽  
High Molecular Weight ◽  
Enhanced Properties

Optimize Performance Through Customization of Paraffin Inhibitor Molecular Structure

2021 ◽  
Author(s):  
Kiran Gawas ◽  
Chandrashekhar Khandekar ◽  
Katrina Akita ◽  
Janet Ngo ◽  
John Hazlewood
Keyword(s):  
Molecular Weight ◽  
Maleic Anhydride ◽  
High Molecular Weight ◽  
Gas Production ◽  
Performance Study ◽  
Oil Composition ◽  
Scanning Calorimetry ◽  
Test Conditions ◽  
Alpha Olefin ◽  
The Impact

Abstract Deposition of high molecular weight paraffins and subsequent plugging is one of the most prevalent flow assurance risks in both onshore and offshore oil and gas production. Several thermal (e.g., insulation, heat treatment), mechanical (e.g., pigging, cutting), and chemical (e.g., paraffin crystal modifiers, dispersants, and solvents) techniques are used for wax deposition prevention and remediation. Various chemistries such as long-chain poly alkyl acrylates, olefin vinyl acetate copolymers, alkyl phenol resins and esterified olefin maleic anhydride polymers are used as wax crystal modifiers. This study investigates the impact of the alpha olefin maleic anhydride co-polymers structure on the composition and deposition of paraffin. Eight different crude samples from condensates to black oils with API gravity in the range of 30 to 50° were studied. The focus of this research is on paraffin inhibitors’ effectiveness in reducing paraffin deposition that is driven by thermal driving force between the bulk oil and the pipe wall. Inhibitor performance was measured by cold finger testing. Three different alpha olefin (short, medium and long) maleic anhydrides esterified with different fatty alcohols with varying chain lengths were tested for performance. The impact of selected chemicals on amount and composition of paraffin deposit under different test conditions was studied. Wax deposit composition was characterized using high temperature gas chromatography (HTGC) and differential scanning calorimetry (DSC) techniques. Effect of pendant side chain length as well as the composition and molecular weight of the alpha-olefin backbone on paraffin inhibition is presented. Additionally, the impact of test conditions on the composition and hence the performance of the selected chemicals is investigated. We present our findings on selective inhibition of lower molecular weight paraffin depending on the composition of the oil, leaving a much harder deposit rich in high molecular weight paraffin. This is an important observation since a hard deposit would be extremely difficult to remediate in the field and should be avoided. In summary this work provides guidelines for tailoring paraffin inhibitor molecules based on crude oil composition and field conditions, through a systematic structure-performance study.

Low Dielectric, Hydrophobic Polyimide Homopolymers and Poly(Siloxane Imide) Segmented Copolymers for Electronic Applications

1989 ◽  
Vol 154 ◽  
Author(s):  
C. A. Arnold ◽  
Y. P. Chen ◽  
D. H. Chen ◽  
M. E. Rogers ◽  
J. E. McGrath
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Dielectric Constant ◽  
Maleic Anhydride ◽  
High Molecular Weight ◽  
Water Sorption ◽  
Dielectric Constants ◽  
Thermal And Mechanical Properties ◽  
Low Dielectric ◽  
Enhanced Solubility

AbstractPolyimides generally possess excellent thermal and mechanical properties, making them attractive candidates for high performance applications. To be useful for microelectronic applications, however, these materials must also be good insulators, as well as be readily processable.The incorporation of flexible polysiloxane segments into the polyimide backbone structure has been shown to yield soluble, processable copolyimides with good thermal and mechanical properties. In addition, the siloxane component imparts a number of other significant benefits for electronic applications. These include reduced water sorption, surface modification, good thermal and ultraviolet stability, and resistance to degradation in oxygen plasma environments. For polar polyimide systems, siloxane incorporation will also reduce the dielectric constant. The use of other less polar, more hydrophobic monomers will consistently yield soluble systems with lower dielectric constants as well.In this work, a series of high molecular weight, soluble polyimide homopolymers and segmented polysiloxane-polyimide copolymers were synthesized by a solution technique. The solution procedure, conducted at lower temperatures (˜170°C) than the classical bulk thermal imidization (300°C), has been shown to yield polyimides of enhanced solubility. In order to further enhance processability, molecular weight was controlled through the incorporation of monofunctional reagents such as phthalic anhydride and maleic anhydride, yielding nonreactive or potentially reactive endgroups, respectively. A series of maleic anhydride terminated imide oligomers with varying molecular weights were synthesized based upon the hexafluoropropane linked dianhydride and bisaniline diamine. In their oligomeric state, they exhibited enhanced solubility compared with their linear high molecular weight analogue. As these monomers were relatively nonpolar and hydrophobic, they afforded polyimides of low dielectric constant and a low level of water sorption. After thermally crosslinking the endgroups, the advantages of insoluble network systems could be realized. Particular advantages for electronic applications include thermal and dimensional stability over a wide temperature range, good mechanical properties, and chemical resistance. Structure-property characterization, including water sorption, dielectric constants, solubility behavior and thermal/mechanical properties will be reported.

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