Preparation and properties of compatible starch-polycaprolactone composites: Effects of hard segments in the polyurethane compatibilizer

Abstract

In this study, polycaprolactone (PCL)‐based polyurethane prepolymers (PCLPU) with different types of hard‐segments were used as compatibilizers to prepare compatible starch‐PCL composites in an intensive mixer. The effects of the hard‐segments in the PCLPU compatibilizers on the structure and properties of the compatible starch‐PCL composite were analyzed thoroughly. The results showed that the addition of the PCLPU compatibilizer to the composites successfully improved the compatibility between starch and PCL. Also, since the NCO content of the different PCLPU compatibilizers was similar, the major factor that affected the structure and properties of the compatible starch‐PCL composites was the difference in the interactions between the PCL matrix and the different PCLPU compatibilizers. The physical crosslinking between the PCL matrix and the PCLPU with aromatic diisocyanate‐based hard‐segments was stronger than that between the PCL matrix and the PCLPU with aliphatic diisocyanate‐based hard‐segments due to the smaller degree of phase separation that occurred in the PCLPU with aromatic diisocyanate‐based hard‐segments. Additionally, analyses of the emission scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), wide‐angle X‐ray diffraction (WAXRD), and mechanical testing results of the composites showed that the compatibility between the starch and the PCL was improved significantly by the existence of the strong physical cross‐linking between the PCLPU compatibilizer and the PCL matrix. Toward this end, the PCLPU with aromatic diisocyanate‐based hard‐segments improved the compatibility between the starch and the PCL better than the PCLPU with aliphatic diisocyanate‐based hard‐segments, and thereby boosted the overall performance of the composite materials to a higher degree.

Effect of special structure of clam shell powder on structure and properties of castor oil‐based composites

“…The bands at 2850 and 2930 cm −1 were assigned to the vibration of CH bond 17,40,41 . It should be noted that the peak for the isocyanate group (‐NCO) in COPU and COC‐50 appeared at about 2272 cm −1 , however, the same ‐NCO peak for COS‐50 and COs‐50 appeared as weak peaks as shown in Figure 2(a) 42–44 . These phenomena indicated that CSP consumed the ‐NCO group in COPU more easily than CaCO 3 because the polysaccharide protein components in CSP contain active groups (such as ‐OH, ‐NH‐, etc.)…”

Polyurethane Prepolymer Modified Cassava Starch Based Poly(butylene adipate‐co‐terephthalate) Composites with Excellent Compatibility and High Toughness

“…The fracture surface of MSPT-2 was smoother and more continuous compared with that of MSPT-3, MSPT-4. It should be pointed out that SEM images of MSPT-2, MSPT-3, and MSPT-4 exhibited the granular structure of MS. [22] The observation indicated that the reaction between the OH groups of starch and the NCO groups of PUP occurred on the surface of starch granules, and the structure of MS was not destroyed during the melting blending of the composites.…”

“…In fact, using Wu's method to prepare the modified starch, we only need to improve the compatibility between PUP and MPBAT. Besides, Koranteng et al have used PCL‐based polyurethane prepolymers (PCLPU) as a compatibilizer to prepare compatible starch‐PCL composite. It motivated us to hypothesize that PUPs modified starch may improve the interfacial compatibility and strength in the starch‐based materials.…”

Preparation, Characterization, and Biodegradability Assessment of Maize Starch‐(PVOH)/Clay Nanocomposite Films

“…Due to their platelet like structure, layered silicate nanoclays such as montmorillonite (MMT) and kaolinite are the most discussed nanosized fillers for the improvement of barrier properties and potential enhancement of the mechanical performance of polymer films. [1,2] The most studied matrices for such applications are based on starch and cellulose derivatives, [3,4] polylactic acid (PLA), [6,7] polycaprolactone (PCL), [8,9] and poly-(butylene succinate) (PBS). [10,11] Starch is of great interest because it is abundant, cheap, renewable, and biodegradable, but it lacks in strength, water resistance, processability, and thermal stability.…”