A novel method to improve the thermal stability of poly(propylene carbonate)

2014 ◽  
Vol 5 (14) ◽  
pp. 4245-4250 ◽  
Author(s):  
Jingjing An ◽  
Yucai Ke ◽  
Xinyu Cao ◽  
Yongmei Ma ◽  
Fosong Wang

The introduction of NP-10P by simple melt-blending can significantly improve the thermal stability of PPC. This new finding will facilitate development and widespread applications of this biodegradable material.

2018 ◽  
Vol 19 (12) ◽  
pp. 3723 ◽  
Author(s):  
Shaoyun Chen ◽  
Min Xiao ◽  
Luyi Sun ◽  
Yuezhong Meng

The terpolymerization of carbon dioxide (CO2), propylene oxide (PO), and cyclohexene oxide (CHO) were performed by both random polymerization and block polymerization to synthesize the random poly (propylene cyclohexene carbonate) (PPCHC), di-block polymers of poly (propylene carbonate–cyclohexyl carbonate) (PPC-PCHC), and tri-block polymers of poly (cyclohexyl carbonate–propylene carbonate–cyclohexyl carbonate) (PCHC-PPC-PCHC). The kinetics of the thermal degradation of the terpolymers was investigated by the multiple heating rate method (Kissinger-Akahira-Sunose (KAS) method), the single heating rate method (Coats-Redfern method), and the Isoconversional kinetic analysis method proposed by Vyazovkin with the data from thermogravimetric analysis under dynamic conditions. The values of ln k vs. T−1 for the thermal decomposition of four polymers demonstrate the thermal stability of PPC and PPC-PCHC are poorer than PPCHC and PCHC-PPC-PCHC. In addition, for PPCHC and PCHC-PPC-PCHC, there is an intersection between the two rate constant lines, which means that, for thermal stability of PPCHC, it is more stable than PCHC-PPC-PCHC at the temperature less than 309 °C and less stable when the decomposed temperature is more than 309 °C. Pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and thermogravimetric analysis/infrared spectrometry (TG/FTIR) techniques were applied to investigate the thermal degradation behavior of the polymers. The results showed that unzipping was the main degradation mechanism of all polymers so the final pyrolysates were cyclic propylene carbonate and cyclic cyclohexene carbonate. For the block copolymers, the main chain scission reaction first occurs at PC-PC linkages initiating an unzipping reaction of PPC chain and then, at CHC–CHC linkages, initiating an unzipping reaction of the PCHC chain. That is why the T−5% of di-block and tri-block polymers were not much higher than that of PPC while two maximum decomposition temperatures were observed for both the block copolymer and the second one were much higher than that of PPC. For PPCHC, the random arranged bulky cyclohexane groups in the polymer chain can effectively suppress the backbiting process and retard the unzipping reaction. Thus, it exhibited much higher T−5% than that of PPC and block copolymers.


2011 ◽  
Vol 233-235 ◽  
pp. 1786-1789 ◽  
Author(s):  
Li Sha Pan ◽  
Nai Xu ◽  
Zheng Tian ◽  
Ling Bin Lu ◽  
Su Juan Pang ◽  
...  

PPC is a new biodegradable aliphatic polycarbonate with poor thermal stability and mechanical properties which is difficult to form sheets or films and so on. Through the addition of alkali lignin, thermal stability and mechanical properties of PPC was improved largely. PPC/ alkali lignin sheets could be prepared. DSC results showed that the thermal stability of PPC was improved by the introduction of alkali lignin. SEM showed good dispersion of alkali lignin particles into PPC matrix that resulted in good miscibility. Improved mechanical properties and thermal stability of PPC/ alkali lignin blends were attributed to stronger interfacial interaction of PPC and alkali lignin. These results indicate that blending PPC with alkali lignin is an efficient and convenient method to improve the properties of PPC.


2014 ◽  
Vol 2014 ◽  
pp. 1-9
Author(s):  
Iwona Zarzyka

The work focuses on research related to determination of application possibility of new, ecofriendly boroorganic polyols in rigid polyurethane foams production. Polyols were obtained from hydroxypropyl urea derivatives esterified with boric acid and propylene carbonate. The influence of esterification type on properties of polyols and next on polyurethane foams properties was determined. Nitrogen and boron impacts on the foams’ properties were discussed, for instance, on their physical, mechanical, and electric properties. Boron presence causes improvement of dimensional stability and thermal stability of polyurethane foams. They can be applied even at temperature 150°C. Unfortunately, introducing boron in polyurethanes foams affects deterioration of their water absorption, which increases as compared to the foams that do not contain boron. However, presence of both boron and nitrogen determines the decrease of the foams combustibility. Main impact on the decrease combustibility of the obtained foams has nitrogen presence, but in case of proper boron and nitrogen ratio their synergic activity on the combustibility decrease can be easily seen.


2018 ◽  
Vol 2018 ◽  
pp. 1-5 ◽  
Author(s):  
Juan Li

The composites of HIPS/MWNT were prepared by melt blending. The effects of the content of MWNT on the flow, mechanical, and flame retardancy properties of the composites were investigated. The morphologies of fracture surfaces were characterized through scanning electron microscopy (SEM). And the thermal stability of the composites was studied by thermogravimetric analysis. The results show that the flow properties, the impact strength, the elongation at break, and the flame retardancy are improved with the proper addition of MWNT. The morphological behavior indicates the fracture surface of HIPS/MWNT is more roughness than that of HIPS. The addition of MWNT has little influence on the thermal stability of HIPS.


2011 ◽  
Vol 79 ◽  
pp. 282-287 ◽  
Author(s):  
Yi Chen ◽  
Guang Sheng Zeng ◽  
Ping Jiang ◽  
Wei Lu ◽  
Wei Long Huang

EVA was added into PC/PLA blends as a modifier for improving the impact strength of blends, and meanwhile the thermal properties and rheological properties of blends should also be influenced. PC/PLA/EVA blends were prepared by melt blending and the catalyst DBTO was added into the blends in blending process to catalyze the transesterification of PC and EVA for improving the compatibility of blends. The effects of blend composition and transesterification on the thermal and rheological properties of blends were investigated. The results showed that the addition of EVA could improve the crystallinity of PLA in PC/PLA/EVA blends but had little influence on the thermal stability of blends,and the transesterification was beneficial to both the crystallization of PLA and thermal stability of blends. The addition of EVA and the transesterification of PC and EVA increased the apparent viscosity of blends, while the apparent viscosity of blends decreased drastically and the pseudo-plasticity characteristic of blend melts was weakened obviously with increasing PLA content and rising temperature.


2010 ◽  
Vol 148-149 ◽  
pp. 979-982
Author(s):  
Xin Long Wang ◽  
Jin Li

The nano poly(phenylsilsesquioxane) particles (nano-PPSQ) were prepared with both basic and acidic catalyzed processes and the PP/nano-PPSQ composites were prepared by melt blending method. The morphology and thermal stability of PP/nano-PPSQ composites were characterized by SEM, XRD and TGA. The SEM results showed that the particles were well dispersed in the PP matrix and the XRD revealed that the addition of nano-PPSQ influences the crystallinity of PP. The thermogravimetric analysis results of the PP/ nano-PPSQ composites indicated that the incorporation of nano-PPSQ can improve the thermal stability of PP obviously.


Sign in / Sign up

Export Citation Format

Share Document