Severity: Warning
Message: file_get_contents(https://...@pubfacts.com&api_key=b8daa3ad693db53b1410957c26c9a51b4908&a=1): Failed to open stream: HTTP request failed! HTTP/1.1 429 Too Many Requests
Filename: helpers/my_audit_helper.php
Line Number: 176
Backtrace:
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 176
Function: file_get_contents
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 250
Function: simplexml_load_file_from_url
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 3122
Function: getPubMedXML
File: /var/www/html/application/controllers/Detail.php
Line: 575
Function: pubMedSearch_Global
File: /var/www/html/application/controllers/Detail.php
Line: 489
Function: pubMedGetRelatedKeyword
File: /var/www/html/index.php
Line: 316
Function: require_once
The construction of a graft copolymer is an effective method to modify the properties of CO2-based aliphatic polycarbonate (CO2-APC) for meeting specific needs. Herein, we describe a facile route for the synthesis of CO2-based APC-graft-polystyrene copolymers using a "grafting from" strategy. Firstly, the copolymerization of CO2 and epichlorohydrin (ECH) was performed for the synthesis of the APC of poly(CO2/ECH). Then, a functionalized-APC can be prepared by the substitution reaction of poly(CO2/ECH) and 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) that can serve as a precursor for the graft compolymer of P(CO2/ECH)-g-polystyrene via nitroxide-mediated radical polymerization (NMRP). The intermediates at each step and final graft copolymers were characterized using 1H NMR, GPC, DSC and TG analyses.
Download full-text PDF |
Source |
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http://dx.doi.org/10.1039/d0cc03665j | DOI Listing |
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