Elsevier

Polymer

Volume 42, Issue 2, January 2001, Pages 839-845
Polymer

Polymer Communication
Synthesis and characterization of new polyamide-imides containing pendent adamantyl groups

https://doi.org/10.1016/S0032-3861(00)00379-7Get rights and content

Abstract

A new diimide-dicarboxylic acid, 4-(1-adamantyl)-1,3-bis(4-trimellitimidophenoxy)benzene (ADBTB), containing pendent adamantyl group was synthesized in three steps starting from adamantyl resorcinol. A series of new adamantyl-containing polyamide-imides (PAIs) were prepared by direct polycondensation of ADBTB and various aromatic diamines in N-methyl-2-pyrrolidinone (NMP) using triphenyl phosphite and pyridine as condensing agents. These PAIs produced had inherent viscosities of 0.72–0.94 dl g−1. All the PAIs were readily dissolved in various solvents such as N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, pyridine, cyclohexanone and tetrahydrofuran. These PAIs were solution-cast from DMAc solutions into transparent, flexible, and tough films except for PAI-5 polymer film. Wide-angle X-ray measurement revealed that all the polymers were amorphous. These PAIs had glass transition temperatures between 230–254°C and 10% weight loss temperatures in the range of 467–491°C in nitrogen atmosphere. The polymer films had a tensile strength range of 67–110 MPa and a tensile modulus range of 2.1–2.6 GPa.

Introduction

Aromatic polyimides are well recognized as a class of high performance materials due to their remarkable thermal and oxidative stabilities and excellent electrical and mechanical properties for long time periods of operation [1], [2]. Unfortunately, strong interaction between polyimide chains and their rigid structure make them intractable. Poor thermoplastic fluidity and solubility are the major problems for wide application of polyimides. Thus, to overcome these processing problems various approaches have been carried out by incorporating flexible units such as –NHCO–, –O–, and –SO2–, and some of which are commercialized [3], [4].

Among them, polyamide-imide (PAI) is the most successful material, which combines the advantages of high-temperature stability and processability. In our previous studies, we have applied the phosphorylation polycondensation technique to prepare novel and soluble PAIs from imide-containing dicarboxylic acids and aromatic diamines [5], [6], [7], [8], [9]. This route provides significant advantages in manufacturing operations compared with conventional methods.

Adamantane is a highly symmetrical tricyclic hydrocarbon which consists of fused chair-form cyclohexane rings [10]. The unique structure of this substance is reflected in highly thermal and oxidative stabilities, and low hydrophobicity. Adamantane has been incorporated into many high-temperature polymers such as poly(ether ether ketone)s [11], polyamides [12], [13], polyimides [13], polysulfones [11], and polycarbonates [14], subsequently producing increased thermal stability, solubility and glass transition temperature. However, there is limited literature reported on the synthesis and characterization of PAI containing adamantyl group.

In the present study, we report the synthesis and characterization of a series of new PAIs containing a pendent adamantyl group. A new adamantyl-containing diimide-dicarboxylic acid, 4-(1-adamantyl)-1,3-bis(4-trimellitimidophenoxy)benzene (ADBTB), was synthesized and polymerized with various synthesized diamines to obtain these PAIs. The crystallinity, solubility, thermal and tensile properties of these PAIs are also discussed.

Section snippets

Materials

Adamantyl resorcinol (ADRL) was prepared by alkylating resorcinol with 1-bromoadamantane in refluxing benzene, m.p. 247–248°C (Lit. [11] 249–250°C). 2,2-Bis[4-(4-aminophenoxy)phenyl]hexafluoropropane (DA-1) [15], 3,3′,5,5-tetramethyl-2,2-bis[4-(4-aminophenoxy)phenyl]propane (DA-2) [16], 1,4-bis(4-aminophenoxy)-2-tert-butylbenzene (DA-3) [17], 1,4-bis(4-aminophenoxy)-2,5-di-tert-butylbenzene (DA-4) [18], 2,2′-dimethyl-4,4′-bis(4-aminophenoxy)biphenyl (DA-5) [19], and

Synthesis of diimide-dicarboxylic acid

The synthetic route to the new adamantyl-containing diimide-dicarboxylic acid monomer, ADBTB, is shown in Scheme 1. The bisphenol compound, adamantyl resorcinol (ADRL), was prepared by alkylating resorcinol with 1-bromoadamantane in refluxing benzene without adding any catalyst [11]. The compound ADRL was reacted with p-chloronitrobenzene in the presence of potassium carbonate and afforded the dinitro compound ADBNB. It was obtained in high yield (90%) and purified by recrystallizing in glacial

Conclusions

This study had successfully synthesized a new diimide-dicarboxylic acid, ADBTB, containing a rigid and bulky adamantyl pendent group. A series of novel PAIs were prepared by the direct polycondensation from the diimide-dicarboxylic acid with various diamines. These PAIs exhibited amorphous nature as well as mechanical properties. The results presented herein also demonstrate clearly that incorporating the adamantyl group into the polymer backbone remarkably enhanced the solubility and thermal

Acknowledgements

The authors thank the National Science Council of the Republic of China for support of this work under grant NSC 88-2216-E011-008.

References (22)

  • D.J. Liaw et al.

    Polymer

    (1999)
  • D.J. Liaw et al.

    Polymer

    (1998)
  • M.K. Ghosh et al.

    Polyimide: fundamentals and applications

    (1996)
  • M.J. Abadie et al.

    Polyimides and other high-temperature polymers

    (1991)
  • D. Wilson et al.

    Polyimide

    (1991)
  • D.J. Liaw et al.

    Chem Mater

    (1998)
  • D.J. Liaw et al.

    J Polym Sci, Part A: Polym Chem

    (1998)
  • D.J. Liaw et al.

    J Polym Sci, Part A: Polym Chem

    (1999)
  • D.J. Liaw et al.

    Macromol Chem Phys

    (1999)
  • D.J. Liaw et al.

    Polym Int

    (1999)
  • L.J. Mathias et al.

    ACS Symp Ser

    (1996)
  • Cited by (0)

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