Enhancement of biodegradable polyesterthermoplastic starch blend properties through ordered molecular orientation

Name: Porawee Katanyoota

LCSH: Kasetsart University -- Dissertations. Ph.D. (Packaging Technology) 2022

Classification :.LCCS: TP1180.B55

LCSH: Kasetsart University. -- Department of Packaging and Materials Technology -- Dissertations

LCSH: Biodegradable plastics

LCSH: Thermoplastics

LCSH: Polyesters

LCSH: Polylactic acid

LCSH: Polybutenes

LCSH: Zeolites

Abstract: This thesis focused on the study of biaxial orientation of biodegradable polyester/thermoplastic starch blends. This work was divided into two parts; the first part reported the effect of the biaxial stretching parameters on properties of a polymer blend consisting of polylactic acid, thermoplastic starch, and poly(butylene adipate-co-terephthalate) (PLA/TPS/PBAT); and the second part focused on both the effects of compounding sequence of zeolite 5A (Z5A) and the biaxial stretching parameters on the properties of PLA/TPS films. For the first part, PLA/TPS/PBAT pellets were prepared by melt blending using a twin-screw extruder and the pellets were subsequently converted into plastic sheet using a single-screw extruder. The sheets were then biaxially stretched into films. The effect of biaxial stretching parameters (stretching rate and annealing time) on the morphological, mechanical, thermal, and gas barrier properties of PLA/TPS/PBAT (40/40/20) films was investigated. The stretching rate and annealing time were varied between 22.5–300 mm/s and 0–180 s, respectively. The biaxial stretching increased the ordered structure and crystallinity of PLA and PBAT in the ternary blend film. The crystallinity of biaxially oriented films determined based on PLA increased with stretching rate and annealing time. The increased ordered structure and crystallinity of PLA/TPS/PBAT films led to improved tensile strength and oxygen barrier properties. For the second part, PLA/TPS/Z5A resins were prepared by melt compounding using a twin-screw extruder prior to cast sheet extrusion and biaxial stretching. Two mixing routes were used to prepare PLA/TPS/Z5A composite pellets. Sequence I (SI): PLA was compounded with Z5A before blending with TPS, and Sequence II (SII): TPS was incorporated with Z5A before blending with PLA. All composite samples were composed of PLA, TPS, and Z5A, using a starch to glycerol weight ratio of 100:35, a PLA: TPS weight ratio of 60:40, and a Z5A content of 1 wt%. The biaxial stretching was carried out at stretching rates of 75– 150 mm/s and annealing at 100 °C for 60 s to prepare stretched PLA/TPS, SI, and SII films (BOPLA/TPS, BOSI, and BOSII). SII mixing sequence improved the miscibility of PLA and TPS. The crystallinity and ordered structure of PLA increased with stretching rate and annealing. The increase in PLA crystallinity provided improvement of mechanical and barrier properties. Moreover, the overall migration of the stretched films was lower than the overall migration limit (10 mg/dm2).

Kasetsart University. Office of the University Library

Address: Bangkok

Email: tdckulib@ku.ac.th

Name: Amporn Sane

Role: Thesis Advisor

Name: Rangrong Yoksan

Role: Thesis CO-Advisor

Name: Piyawanee Jariyasakoolroj

Role: Thesis CO-Advisor

Created: 2022

Modified: 2025-07-27

Issued: 2025-07-27

วิทยานิพนธ์/Thesis

application/pdf

URL: https://www.lib.ku.ac.th/KUthesis/2565/porawee-kat-all.pdf

CallNumber: TP1180.B55 .P67

eng

DegreeName: Doctor of Philosophy

Level: Doctoral Degraee

Descipline: Packaging Technology

Grantor: Kasetsart University

©copyrights Kasetsart University

ลำดับที่.	ชื่อแฟ้มข้อมูล	ขนาดแฟ้มข้อมูล	จำนวนเข้าถึง	วัน-เวลาเข้าถึงล่าสุด
1	porawee-kat-all.pdf	4.22 MB

ใช้เวลา

0.020706 วินาที