東華大學圖書館 |

語系: 繁體中文

說明(常見問題)

回圖書館首頁

手機版館藏查詢

登入

回首頁

切換: 標籤 | MARC模式 | ISBD

Characterization and modification of...

Wei, Liqing.

FindBook

Google Book

Amazon

博客來

Characterization and modification of selected bioplastics.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Characterization and modification of selected bioplastics./
作者:	Wei, Liqing.
面頁冊數:	210 p.
附註:	Source: Dissertation Abstracts International, Volume: 76-09(E), Section: B.
Contained By:	Dissertation Abstracts International76-09B(E).
標題:	Materials science. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3702517
ISBN:	9781321738612

Characterization and modification of selected bioplastics.
Wei, Liqing.

Characterization and modification of selected bioplastics. - 210 p.

Source: Dissertation Abstracts International, Volume: 76-09(E), Section: B.

Thesis (Ph.D.)--University of Idaho, 2015.

Bioplastics are becoming increasingly prominent mainly due to the growing environmental pollutions caused by non-biodegradable plastics. Polyhydroxybutyrate-co-hydroxyvalerate (PHBV), the major copolymer of polyhydroxyalkanoates (PHAs) family, was biosynthesized (by mixed microbial culture fed with fermented diary manure) and characterized. The monomeric composition (HV% ~ 40%) was determined by GC-MS and NMR. ESI-MSn and NMR analyses showed these PHBVs had random co-monomeric sequence distribution; meantime, they showed characteristic properties (crystallinity, single melting, and tensile properties) as studied by DSC and DMA. The homopolymer poly(3-hydroxybutyrate) (PHB), usually shows interesting properties such as high crystallinity and multiple melting behaviors. The effect of thermal history, such as crystallization (isothermal (temepratures = 80 to 140 °C) and nonisothermal (cooling rates = 2 to 50 °C/min)) and melting (heating rates = 5 to 50 °C/min), on the multiple melting behavior of PHB has been studied using conventional and temperature modulated DSC (TMDSC) techniques. Results showed PHB multiple melting was ascribed to the melting-recrystallization-remelting mechanism and its crystallization kinetics varied with crystallization temperatures and cooling rates. The brittleness and poor melt strength properties of the bioplastics PHB and poly L-lactic acid (PLLA) were imporved by two strategies: (i) to modify polymer structures by cross-linking, (ii) to introduce an external component by grafting, which were initiated by dicumyl peroxide (DCP) via reactive extrusion, have been developed. In method (i), rheological measurements showed cross-linked PHB and PLLA (0.25 to 1 wt% DCP) separately had higher melting strength than their linear polymers due to the formation of long chain branching. Their brittleness was reduced because smaller crystal sizes were observed by hot-stage polarized microscope (HS-POM), meanwhile the reduction of crystallinity was positively correlated to DCP levels. For case (ii), cellulose (another abundant renewable material) was grafted onto PHB backbone induced by DCP (2 to 5 wt%). The chemical structures of grafted copolymer and grafting mechanism were studied by ESR, NMR, XRD and FTIR. Results suggested both amorphous and crystalline regions of cellulose were involved in the reaction. The characterization and modification approaches discussed in this dissertation would provide technical guidance to either researches or industrial processing of these bioplastics.

ISBN: 9781321738612Subjects--Topical Terms:

543314
Materials science.

Characterization and modification of selected bioplastics.
LDR:03431nmm a2200289 4500 001 2066980
005 20160321080107.5
008 170521s2015 ||||||||||||||||| ||eng d
020 $a 9781321738612
035 $a (MiAaPQ)AAI3702517
035 $a AAI3702517
040 $a MiAaPQ $c MiAaPQ
100 1 $a Wei, Liqing. $3 3181836
245 1 0 $a Characterization and modification of selected bioplastics.
300 $a 210 p.
500 $a Source: Dissertation Abstracts International, Volume: 76-09(E), Section: B.
500 $a Adviser: Armando G. McDonald.
502 $a Thesis (Ph.D.)--University of Idaho, 2015.
520 $a Bioplastics are becoming increasingly prominent mainly due to the growing environmental pollutions caused by non-biodegradable plastics. Polyhydroxybutyrate-co-hydroxyvalerate (PHBV), the major copolymer of polyhydroxyalkanoates (PHAs) family, was biosynthesized (by mixed microbial culture fed with fermented diary manure) and characterized. The monomeric composition (HV% ~ 40%) was determined by GC-MS and NMR. ESI-MSn and NMR analyses showed these PHBVs had random co-monomeric sequence distribution; meantime, they showed characteristic properties (crystallinity, single melting, and tensile properties) as studied by DSC and DMA. The homopolymer poly(3-hydroxybutyrate) (PHB), usually shows interesting properties such as high crystallinity and multiple melting behaviors. The effect of thermal history, such as crystallization (isothermal (temepratures = 80 to 140 °C) and nonisothermal (cooling rates = 2 to 50 °C/min)) and melting (heating rates = 5 to 50 °C/min), on the multiple melting behavior of PHB has been studied using conventional and temperature modulated DSC (TMDSC) techniques. Results showed PHB multiple melting was ascribed to the melting-recrystallization-remelting mechanism and its crystallization kinetics varied with crystallization temperatures and cooling rates. The brittleness and poor melt strength properties of the bioplastics PHB and poly L-lactic acid (PLLA) were imporved by two strategies: (i) to modify polymer structures by cross-linking, (ii) to introduce an external component by grafting, which were initiated by dicumyl peroxide (DCP) via reactive extrusion, have been developed. In method (i), rheological measurements showed cross-linked PHB and PLLA (0.25 to 1 wt% DCP) separately had higher melting strength than their linear polymers due to the formation of long chain branching. Their brittleness was reduced because smaller crystal sizes were observed by hot-stage polarized microscope (HS-POM), meanwhile the reduction of crystallinity was positively correlated to DCP levels. For case (ii), cellulose (another abundant renewable material) was grafted onto PHB backbone induced by DCP (2 to 5 wt%). The chemical structures of grafted copolymer and grafting mechanism were studied by ESR, NMR, XRD and FTIR. Results suggested both amorphous and crystalline regions of cellulose were involved in the reaction. The characterization and modification approaches discussed in this dissertation would provide technical guidance to either researches or industrial processing of these bioplastics.
590 $a School code: 0089.
650 4 $a Materials science. $3 543314
650 4 $a Wood sciences. $3 3168288
650 4 $a Environmental health. $3 543032
690 $a 0794
690 $a 0746
690 $a 0470
710 2 $a University of Idaho. $b Natural Resources. $3 3169373
773 0 $t Dissertation Abstracts International $g 76-09B(E).
790 $a 0089
791 $a Ph.D.
792 $a 2015
793 $a English
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3702517