Rigid and flexible polyurethane foams production from palm oil-based Polyol

Lee, Choy Sin (2008) Rigid and flexible polyurethane foams production from palm oil-based Polyol. PhD thesis, University of Malaya.

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Official URL: http://dspace.fsktm.um.edu.my/handle/1812/607


Polyurethane foams are amongst the most important class of specialty polymers. It can be divided into three major classes, namely rigid, semi-rigid and flexible polyurethane foams. According to M.L. Kerman (2005), the global polyurethane market in 2004 showed that flexible polyurethane foams contributed 47% of the market share, followed by 26% of rigid foams, and 27% of other applications in coatings, adhesives, sealants and elastomers (CASE), binders, foundry and machinery. Rigid polyurethane foams are particularly useful in the construction industries as they are used as components such as polymeric concretes, insulating materials and sealants. In addition, flexible polyurethane foams are as cushion in the furniture, bedding and automotive industries. Conventionally, polyol is mainly derived from petrochemicals. They play an important role in the polyurethane industry. However, in view of the environmental and sustainability issues, the use of vegetable oil-derived polyol can serve as a substitute in the polyurethane industry. Malaysia is one of the major producers of palm oils. Therefore, the utilization of palm oils in the synthesis of polyols for both rigid and flexible polyurethane foams was initiated in this study. In this study, epoxidized diethanolamides was produced as a new type of polyol by reacting diethanolamine (DEA) with various ratio of Epoxidized Palm Olein (EPOo) to Refined Bleached Deodorized Palm Kernel Olein (RBDPKOo). The products were further reacted with diisocyanate and catalyzed by AlCl3-THF to produce rigid polyurethane. Concurrent with the production of rigid polyurethane, two minor important side-products oxazolidones and isocyanurates were produced to give significantly a better quality of rigid polyurethane. This is due to epoxidized diethanolamides with higher oxirane oxygen contents (OOC) that produced rigid polyurethane foams of higher compression strength (338.8 kPa), close cell contents (97.95%) and lower thermal conductivity (0.0288 w/m.K). In this work, only epoxides in diethanolamide polyol was reacted with isocyanate that resulted in the formation of hard segments oxazolidone and isocyanurate in the rigid polyurethane and this improved the compression strength and close cell contents of the foam. In addition, higher OOC in diethanolamides also gave better dimensional stability to the rigid foam that was conditioned at 70 °C and -25 °C. Apart from mechanical improvements, epoxides that were retained in diethanolamide structure also improved the thermal stability of the rigid foam. Thermogravimetric Analysis (TGA) was recorded with higher decomposition temperature for foam produced with higher OOC diethanolamides. Formation of oxazolidones in the urethane backbones and isocyanurates exhibited good-heat resistance that significantly enhanced the thermal stability of the foams. Index 1.40 was determined to be the most suitable isocyanate index when the polyurethane foam were altered by isocyanate index from 0.90 to 1.10. It produced non-brittle rigid foam with the lowest thermal conductivity (0.0288 w/m.K) and the highest close cell contents (97.95%) while maintaining moderate compression strength (338.8 KPa). One type of polyester polyol is synthesized by ring opening of synthetic epoxidized resins with dicarboxylic acids. Conventionally, the epoxides that used in the preparation of polyester polyol were ethylene oxide, propylene oxide, phenylglycidyl ether (PGE), diglycidyl ether of bisphenol A (DGEBA) and 3-phenoxy-1,2-epoxypropane. The versatile polyols were used mainly as fat-based non-ionic detergent, surface active agent, thermoplastic, paper coating resin and material for radiation shielding materials, curable printing ink and as coating. Therefore, in the second part of this study polyester polyol was prepared by using EPOo as the starting material instead of the synthetic epoxy resin. The polyester polyol was synthesized by reacting EPOo with different carbon chain length of aliphatic dicarboxylic acids ranging from C6 to C12. This produced a new type of polyol. The new polyol was mixed thoroughly with 50% of commercial polyol and they were reacted with toluene diisocyanate (TDI) to produce flexible polyurethane foam. The flexibility of the polyurethane foam was due mainly to the high average molecular weight and hydroxyl functional groups that were attached to the carbon chain of the polyols. Longer carbon chain in dicarboxylic acid was found to be more reactive than the shorter chain, which resulted in lower OOC (0.42%) of polyol mixture with bigger average molecular weight (Mw= 10526 g/mol). However, it also produced polyester polyol with higher hydroxyl value (103.6 mg KOH/g sample), viscosity (9755.21 cP at 25 °C, 4222.41 cP at 40°C), cloud point (20.04 °C) and pour point (12.00 °C) when compared to shorter carbon chain of dicarboxylic acid. Longer carbon chain of dicarboxylic acid used to produce polyester polyol resulted in the improvement of the foam properties such as hysteresis (22.76%), elongation at break (181.1 %) and thermal stability. The temperature of the decomposition peak (Tdec) of polyurethane as shown in DSC analysis and the decomposition temperatures of 10%, 50% and 90% of foam weight loss in TG analysis were increased. But, polyol synthesized from shorter carbon chain of dicarboxylic acid produced foam with better tensile stress and tear resistant ability. Isocyanate index 1.00 was selected as the optimal index as it produced flexible foam with the lowest hysteresis (23.64%), highest tensile stress (138.0%) and the best tear resistant ability (0.2382 N/mm). Flexible foam produced from higher isocyanate index was determined to be more stable thermally. However, alteration of isocyanate index did not produce foam with significant changes in terms of cellular structure, but the open cell contents of the foams prepared with different isocyanate index and polyester polyol were in a satisfactory range of 95-97%. Based on physical evaluation, 2 g of water content was the most suitable amount to be used in the production of flexible foams in comparison to 3 g and 4 g of water contents. This was mainly because 2 g of water content produced foam with the lowest hysteresis, highest elongation at break and better tear resistance ability. Nevertheless, increment of water content increased the foams’ open cell contents from 95% to 98% due to the emission of carbon dioxide generated from the reaction of isocyanate with water to form hard segment urea. Therefore, foam with higher content of urea that produced by higher water content as blowing agent were determined to be more stable thermally. Optical microscope also recorded open cells in various pentagon sizes that produced cells of bigger sizes in higher water content produced foam whereas lower water content produced foams with smaller cells in size and also more uniform in structure. ABSTRAK Busa poliuretana merupakan salah satu jenis polimer yang penting dan boleh turut dibahagikan kepada tiga kelas utama, iaitu, busa keras, semi-keras dan fleksibel. Menurut kepada M.L. Kerman (2005), pasaran poliuretana dunia pada 2004 menunjukkan bahawa poliuretane fleksibel menyumbang 47%, diikuti oleh 26% busa keras dan 27% aplikasi lain. Busa keras sangat berguna dalam industri pembinaan iaitu sebagai bahan konkrit, penebat haba dan sebagainya. Di samping, poliuretana fleksibel iaitu kusyen digunakan dalam industri perabot. Kebanyakan poliol yang memainkan peranan utama dalam industri poliuretana adalah dihasilkan dari bahan kimia petrol. Memandangkan isu pemuliharaan dan persekitaran yang mustahak, penggunaan poliol yang berasaskan minyak sayur amat dipentingkan. Malaysia merupakan salah sebuah negara penghasilan minyak kelapa sawit yang utama, oleh demikian, kerja penyelidik ini menggunakan minyak kelapa sawit untuk mensintesiskan dua jenis poliol yang boleh digunakan dalam pembuatan busa keras dan busa fleksibel. Poliol dietanolamida dengan kumpulan epoksi telah dihasilkan sebagai sejenis poliol baru di mana dietanolamina ditindakbalaskan dengan pelbagai nisbah Epoxidized Palm Olein (EPOo) dan Refined Bleached Deodorized Palm Kernel Olein (RBDPKOo). Poliol ini kemudiannya ditindakbalaskan dengan diisosianat dan dengan kehadiran katalis AlCl3-THF untuk menghasilkan poliuretana keras. Dua jenis hasil sampingan, iaitu “oxazolidone” dan isosianurat telah dihasilkan dan telah memperbaiki mutu busa keras. Ini adalah kerana dietanolamida yang mempunyai kumpulan epoksi telah menghasilkan poliuretana keras yang lebih bermutu dari segi mekanik dan kestabilan haba. Busa tersebut adalah stabil apabila disimpan pada suhu 70 °C dan -25 °C. Analisa termagravimetrik (TGA) menunjukkan bahawa suhu penguraiaan busa adalah lebih tinggi apabila dietanolamida yang mengandungi epoksi yang lebih tinggi digunakan dalam tindakbalas penghasilan busa. Indeks isosianat 1.40 telah dipilih sebagai indeks optima disebabkan penghasilan busa yang tidak rapuh serta berkekonduksian haba(0.0288 w/m.K) yang lebih rendah, berkekuatan ketegangan (338.8 kPa) dan berkandungan sel tertutup (97.95%) yang tertinggi. Poliester poliol juga disintesiskan dengan pembukaan kumpulan epoksi dari EPOo dengan asid dikarboksilik yang berantai C6 ke C12. Poliester poliol ini dicampur separuh dengan poliol polieter komersial dan seterusnya ditindakbalaskan dengan toluena diisosianat dalam penyediaan busa fleksibel. Asid dikarboksilik yang berantai lebih panjang didapati adalah lebih reaktif dengan menghasilkan poliol yang bernilai hidroksi yang lebih tinggi (103.6 mg KOH/g sample). Busa yang dihasilkan juga mempunyai nilai “hysteresis” yang lebih rendah, nilai pemanjangan sehingga putus yang lebih tinggi serta kestabilan haba yang lebih baik. Suhu penguraian yang dikaji dengan analisa TGA dan “Differential Scanning Calorimeter” (DSC) bagi busa yang dihasilkan oleh poliester poliol berantai panjang didapati adalah lebih tinggi. Akan tetapi, busa yang dihasilkan oleh poliol berantai pendek mempunyai nilai kekuatan ketegangan dan ketahanan dikoyak yang lebih tinggi. Indeks isosianat 1.00 dan kandungan air 2 g yang digunakan sebagai agen peniup dalam formula penghasilan busa fleksibel telah dipilih sebagai indeks dan kandungan air yang optima. Mikroskop optik menunjukkan sel-sel terbuka dalam busa adalah berbentuk pentagon dan mempunyai saiz-saiz yang tidak seragam bergantung kepada kandungan air yang digunakan semasa penghasilan busa.

Item Type: Thesis (PhD)
Subjects: Q Science > Q Science (General)
Date Deposited: 31 Jul 2013 03:07
Last Modified: 31 Jul 2013 03:07
URI: http://repository.um.edu.my/id/eprint/1191

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