Effect of polymerization conditions on the polylactic acid properties

Zavrazhnov, S. A.; Fomin, V. A.; Beloded, L.N.; Lobaeva, T. S.

doi:10.1134/s1070427212080216

Cited by 4 publications

(5 citation statements)

References 6 publications

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“…These results prove that SnCl 2 is capable to produce high T m poly(L-lactide) in analogy to the previously Fig. 2 CO signals of the 13 C NMR spectra of poly(L-lactide) s prepared with SnCl 2 a at 160 °C/2 h (No. 4B, Table 1) and b at 190 °C/1.5 h (No.3, 3), b neat SnCl 2 at 140 °C /48 h (No.…”

Section: Polymerizations At 140 °Csupporting

confidence: 84%

“…4B and 5B of Table 1and Nos. 2-4 of Table 2 were subject to high-resolution 13 C NMR measurements (150 MHz) with a s/n ratio > 200/1. All spectra were identical, and the CO or CH signals, which are particular sensitive to the presence of different stereosequences were perfectly symmetrical and did not display a presence of L-D/D-L tetrads.…”

Section: Polymerizations With Neat Sncl 2 At 160 and 180 °Cmentioning

confidence: 99%

“…amidines) as nontoxic substitute of tin(II) salts [6][7][8][9][10][11]. As example, the LD 50 doses of pyridine has been found to be 500 mg Kg −1 and 4-N,N-dimethylamino pyridine is even ten times more toxic than pyridine [12,13]. On the other hand, the increasing delivery of Sn(II) salts to the environment due to decomposition of polylactides or their hydrolysis in oceans, does not cause concern about environmental pollution.…”

Section: Introductionmentioning

confidence: 99%

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Polymerization of l-lactide with SnCl2: A Low Toxic and Eco-friendly Catalyst

Kricheldorf

Weidner

2021

J Polym Environ

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Polymerizations of l-lactide catalyzed either by neat SnCl2 or by SnCl2 + difunctional cocatalysts were conducted in bulk at 180, 160 and 140 °C with variation of the Lac/Cat ratio and time. With neat SnCl2 poly(L-lactide) having weight average molecular weights (uncorrected Mw’s) up to 190 000 g mol−1 were obtained mainly consisting of linear chains. Addition of salicylic acid or 1,1-bisphenol yielded a higher fraction of cyclic polylactides but lower molecular weights. Furthermore, SnCl2 was compared with Bu2SnCl2 and various other metal chlorides and the best results were obtained with SnCl2. With ethyl L-lactate as initiator SnCl2-catalyzed ROPs were performed at 120 °C and the lac/initiator ratio was varied. All these experiments were conducted under conditions allowing for comparison with ROPs catalyzed with neat Sn(II)-2-ethyhexanoate. Such a comparison was also performed with ε-caprolactone as monomer.

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Section: Polymerizations At 140 °Csupporting

confidence: 84%

Section: Polymerizations With Neat Sncl 2 At 160 and 180 °Cmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Polymerization of l-lactide with SnCl2: A Low Toxic and Eco-friendly Catalyst

Kricheldorf

Weidner

2021

J Polym Environ

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“…In the case of SnCl 2 the majority of papers deal with its application as polycondensation catalyst, an aspect which will be discussed in part 8. Only a handful ROPs of LLA catalyzed with neat SnCl 2 were studied by Zavrazhnov et al 214 Those experiments were conducted in bulk at 120-160 °C with a high concentration of catalyst. Only low M w 's < 16 000 were obtained whereas SnOct 2 gave higher M w 's under identical conditions.…”

Section: Various Tin Compounds As Catalystsmentioning

confidence: 99%

Syntheses of polylactides by means of tin catalysts

Kricheldorf

Weidner

2022

Polym. Chem.

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“…In two more recent papers focused on the preparative aspects of ROPs catalysed by neat SnOct 2 or its combination with triphenylphosphine no information on the polymerization mechanism or topology is disclosed. 32,33 In this context, the present study served three purposes. First, it should be revealed to what extent the molar mass depends on the Lac/Cat ratio and on the temperature.…”

Section: Introductionmentioning

confidence: 99%