The influence of processing parameters on mechanical and morphological properties of TPVs base on natural rubber and polypropylene blends: A statistics approach

2021 ◽  
Author(s):  
Nataphon Phupewkeaw ◽  
Pattarawit Srimuang
Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 199
Author(s):  
Theerarat Sengsuk ◽  
Ponusa Songtipya ◽  
Ekwipoo Kalkornsurapranee ◽  
Jobish Johns ◽  
Ladawan Songtipya

A novel active bio-based pressure-sensitive adhesive incorporating cinnamon oil (Bio-PSA/CO) obtained from the mixture of natural rubber (NR), xyloglucan (XG), and cinnamon oil (CO) for food antimicrobial applications were successfully developed by using a two-roll mill mixer. The effect of the main process factors (i.e., nip gap and mastication time) and XG content on the adhesion properties of the obtained PSA were investigated with different coated substrates including kraft paper, nylon film, polypropylene (PP) film, and aluminum foil (Al). The results suggested that the developed NR-PSA/CO could be applied well to all types of substrate materials. Peel strength and shear strength of the NR-PSA/CO with all substrate types were in the ranges of ~0.03 × 102–5.64 × 102 N/m and ~0.24 × 104–9.50 × 104 N/m2, respectively. The proper processed condition of the NR-PSA/CO was represented with a nip gap of 2 mm and a mastication time of 15 min. An increase in XG content up to 40–60 phr can improve the adhesion properties of the adhesive. The resulting material could be used as an active sticky patch to extend the shelf-life of food in a closed packaging system. The shelf-life of the food samples (banana cupcake) could be extended from 4 to 9 days with NR-PSA/CO patch.


2016 ◽  
Vol 89 (4) ◽  
pp. 653-670 ◽  
Author(s):  
Anu Mary Joseph ◽  
Benny George ◽  
Madhusoodanan K. N. ◽  
Rosamma Alex

ABSTRACTCarbon black filled natural rubber (NR) vulcanizates were devulcanized at ambient temperature in a two roll mill. The effect of cure system, that is, conventional vulcanization (CV), semiefficient vulcanization (semi EV), and efficient vulcanization (EV) systems, used for vulcanization of the original sample, on the efficiency of devulcanization was studied. The efficiency of devulcanization expressed as percentage devulcanization of the samples calculated from residual crosslink density measurements was correlated with the sol fraction of the devulcanized samples based on Horikx analysis. Using chemical probe analysis, we determined (i) the crosslink distribution pattern of the original sample, (ii) the extent to which the different types of crosslinks—that is, polysulfidic, disulfidic, and monosulfidic crosslinks—have been debonded or broken during the shearing process in the two roll mill, and (iii) the pattern of bond formation during revulcanization. Mechanical shearing predominantly breaks the majority crosslink type (polysulfidic crosslinks in CV and semi EV cure systems and disulfidic crosslinks in EV samples). Irrespective of the significant reduction in total crosslink density in all three sets of samples, chain shortening reactions similar to the post-crosslinking chemical reactions at curing temperatures also occur during mechanical shear at ambient conditions, which increased the absolute value of monosulfidic links in CV and semi EV systems. However, in the devulcanized EV system, the absolute value of polysulfidic crosslinks increased, which might be due to the re-crosslinking of the cleaved bonds. All the devulcanized samples were revulcanized, and the mechanical and morphological properties were analyzed. The percentage retention of the vulcanizate properties after revulcanization of the devulcanized samples correlated very well with efficiency of devulcanization.


2013 ◽  
Vol 844 ◽  
pp. 89-92
Author(s):  
Boripat Sripornsawat ◽  
Azizon Kaesaman ◽  
Charoen Nakason

Maleated natural rubber (MNR) was synthesized and formulated to prepare thermoplastic natural rubber (TPNR) by blending with co-polyamide (COPA). It was found that 100% modulus, tensile strength, elongation at break, hardness and degree of swelling increased with increasing proportion of COPA. However, degree of swelling and tension set value decreased which reflects enhancing of rubber elasticity. Dynamic properties were also determined by a rotor less oscillating shear rheometer (Rheo Tech MDpt). It was found that increasing proportion of MNR caused increasing of storage modulus and complex viscosity but decreasing tan δ value. Morphological properties were also determined by SEM technique. It was found that the MNR/COPA simple blends with the proportion of rubber 40, 50 and 60 wt% exhibited the co-continuous phase structures.


2013 ◽  
Vol 844 ◽  
pp. 239-242 ◽  
Author(s):  
Supaporn Ieadsang ◽  
Anoma Thitithammawong ◽  
Charoen Nakason ◽  
Azizon Kaesaman

Modified epoxidized palm oil (pA-m-EPO) was prepared by a reaction of epoxidized palm oil (EPO) with n-phenyl-p-phenylenediamine. Chemical structure of the pA-m-EPO was characterized by using FT-IR spectrophotometer. Influence of the pA-m-EPO on bound rubber content, total mixing energy, Mooney viscosity and curing characteristics of carbon black filled natural rubber compound together with mechanical and morphological properties of carbon black filled natural rubber vulcanizates was later studied. Results showed that the NR compound and vulcanizate with using the pA-m-EPO gave inferior properties than those of using the aromatic oil. However, they provided better properties than those of the treated distillate aromatic extract (TDAE) excepting filler dispersion. Furthermore, the pA-m-EPO can be claimed as non-carcinogenic processing oil with low polycyclic aromatic hydrocarbons.


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