Polymerization studies with allyl starch

Wilham, C. A.; McGuire, T. A.; Rudolphi, A. S.; Mehltretter, C. L.

doi:10.1002/app.1963.070070419

Cited by 10 publications

(4 citation statements)

References 7 publications

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“…However, since in most cases a first report was never followed up, perhaps these modifications were either unsuccessful or produced unwanted by-products like methods involving halogens (e.g., [ 37 ]). Another reason may be that starch integrity was affected too much, as mentioned by Wilham et al [ 41 ], in substituting starch with allyl groups.…”

Section: Methods To Improve the Graft Selectivitymentioning

confidence: 99%

Grafting Starch with Acrylic Acid and Fenton’s Initiator: The Selectivity Challenge

Noordergraaf,

Witono,

Heeres

2024

Polymers

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Through the graft polymerization of acrylic monomers onto starch, materials with interesting new properties can be synthesized. Fenton’s chemistry, Fe2+/H2O2, is considered to be attractive for the initiation of graft polymerization with the monomer acrylic acid since it is cheap and reacts quickly at ambient conditions and should therefore be easy to scale up. However, the selectivity of the grafting versus the homopolymerization reaction poses a challenge with this monomer and this type of initiator. In the present review paper, we investigate why data from the literature on grafting systems with other monomers and initiation systems tend to show higher graft selectivity. A scheme is presented, based on reaction engineering principles, that supports an explanation for these observed differences. It is found that more selective activation of starch is a factor, but perhaps even more important is a low monomer-to-starch ratio at the starting sites of graft reactions. Since water is the most common solvent, monomers that are less water-soluble have an advantage in this respect. Based on the proposed scheme, methods to improve the graft selectivity with Fenton’s initiator and acrylic acid are evaluated. Most promising appears to be a method of gradual monomer dosage. With gelatinized cassava starch in a batch reactor, both the grafting percentage (17 => 29%) and graft selectivity (18 => 31%) could be improved. This can be considered a principal breakthrough. Still, more research and development would be needed to refine the method and to implement the idea in a continuous reactor at a larger scale.

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Section: Methods To Improve the Graft Selectivitymentioning

confidence: 99%

Grafting Starch with Acrylic Acid and Fenton’s Initiator: The Selectivity Challenge

Noordergraaf,

Witono,

Heeres

2024

Polymers

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“…However, since in most cases the first paper was never followed-up, perhaps they were either unsuccessful or produced unwanted by-products like methods involving halogens. Another reason may be that starch integrity was affected too much, as mentioned by Wilham et al 41 in substituting starch with allyl groups.…”

Section: B) Preceding Process Step(s) and Creation Of Starch Macrorad...mentioning

confidence: 99%

Grafting Starch with Acrylic Acid and Fenton’s Initiator: The Selectivity Challenge

Noordergraaf,

Witono,

Heeres

2023

Preprint

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Perhaps the greatest challenge in the graft copolymerization of acrylic acid onto starch initiated by Fenton’s is the selectivity of the grafting reaction. Low selectivity means that too much of unwanted homopolymer polyacrylic acid is produced. In this paper, it has been analyzed why with this reaction system, involving a water soluble monomer and indirect initiation, the graft selectivity is such a challenge. Several other grafting reactions, especially with monomers of low water solubility or when direct initiation is applied, show a better grafting performance. A scheme is presented based on reaction engineering principles, that supports an explanation of the observed differences. A more selective activation of starch is a factor, but perhaps even more important is a low monomer to starch ratio at the starting sites of graft reactions. Based on these insights, several methods to improve the graft selectivity are evaluated, with the help of literature data but mostly by experimental explorations in our laboratory. Most promising appears to be a dedicated dosage method, to add monomer in portions over time, tested in a batch reactor with gelatinized cassava starch. This way, both grafting percentage and graft selectivity could be improved. Such could not be realized with the more conventional dosage, which is to add all monomer before the start of the reaction. This can be considered a principal breaktrough. Still, more research and development would be needed to refine the method and to implement the idea also in a continuous reactor at larger scale.

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“…1 These modified starches afford new possibilities for applications in protective and decorative coatings for wood, glass, metal, and other surfaces, for coating and impregnating paper and textiles, and for the preparation of laminated products or rigid plastics. 2 Graft copolymers obtained from allyl starch derivatives are also used in heat-cured coatings and in hydrogels [3][4][5][6] and are of interest for the development of drug delivery systems. Conventional syntheses of allyl starch derivatives use allyl halogenides in the presence of catalysts [1][2][3][4][6][7][8][9][10] at high temperatures generally above the gelatinization temperature of native starch.…”

Section: Introductionmentioning

confidence: 99%

“…Graft copolymers obtained from allyl starch derivatives are also used in heat‐cured coatings and in hydrogels3–6 and are of interest for the development of drug delivery systems. Conventional syntheses of allyl starch derivatives use allyl halogenides in the presence of catalysts1–4, 6–10 at high temperatures generally above the gelatinization temperature of native starch. As allyl chloride and allyl bromide are insoluble in water, the reactions are normally performed in polar aprotic media using hazardous solvents 1–3, 7, 8.…”

Section: Introductionmentioning

confidence: 99%

1‐allyloxy‐2‐hydroxy‐propyl‐starch: Synthesis and characterization

Huijbrechts

Huang

Schols

et al. 2007

J. Polym. Sci. A Polym. Chem.

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New reactive unsaturated starch derivatives, 1-allyloxy-2-hydroxy-propylstarches (AHP-starches), were synthesized by the reaction of waxy maize starch (WMS) and amylose-enriched maize starch (AEMS) with allyl glycidyl ether in a heterogeneous alkaline suspension containing NaOH and Na 2 SO 4 . The degree of substitution (DS) was determined by 1 H NMR spectroscopy, and a DS of 0.20 6 0.01 was found for both AHP-WMS and AHP-AEMS, respectively. The AHP derivatives of WMS and AEMS were further characterized with 1 H and 13 C NMR. It was shown that the AHP substitution was located on the C-6 hydroxyl group of the glucose residues in the starch. The substitution pattern of the AHP groups along the polymer chain was randomly clustered, as determined by enzymatic digestion using pullulanase, a-amylase, and amyloglucosidase, followed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis of the digestion products. With X-ray diffraction and scanning electron microscopy, no changes in the granular morphology and crystallinity between the unmodified starches and AHP-starches were detected.

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Polymerization studies with allyl starch

Cited by 10 publications

References 7 publications

Grafting Starch with Acrylic Acid and Fenton’s Initiator: The Selectivity Challenge

Grafting Starch with Acrylic Acid and Fenton’s Initiator: The Selectivity Challenge

Grafting Starch with Acrylic Acid and Fenton’s Initiator: The Selectivity Challenge

1‐allyloxy‐2‐hydroxy‐propyl‐starch: Synthesis and characterization

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